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Transactions in GIS

Impact factor: 0.906 Print ISSN: 1361-1682 Online ISSN: 1467-9671 Publisher: Wiley Blackwell (Blackwell Publishing)

Subject: Geography

Most recent papers:

  • Exploring the anatomy of Geographic Information Systems and Technology (GIS&T) textbooks.
    Amy E. Frazier, Thomas Wikle, Peter Kedron.
    Transactions in GIS. October 20, 2017
    Choosing a textbook is among the most important decisions instructors make in preparation for an academic term. Geographic Information Systems and Technology (GIS&T) textbook development has been influenced by a unique set of circumstances, mainly the rapid development of the discipline within an interdisciplinary environment, which has resulted in a continuous state of evolution. We examine the anatomy of GIS&T textbooks through a comparison of their organization, content, and depth of coverage. Specifically, utilizing the Geographic Information Science and Technology Body of Knowledge (BoK) as a comprehensive reference, we categorize the content of 26 of the most widely used introductory GIS textbooks. Our results show that there has been consistent coverage of topics over time, with analytical methods and geospatial data being the most prominent topics covered in texts. However, individual textbooks place varying emphasis on the BoK knowledge areas, which is potentially useful to instructors seeking books that emphasize particular knowledge areas. Additionally, long‐term trends indicate a shift toward an emphasis on new forms of geospatial data (e.g., social media). Ongoing efforts to expand and revise the BoK reflect how the discipline continues to manage its own evolution as new geographic research linked to GIS and GIScience emerges.
    October 20, 2017   doi: 10.1111/tgis.12301   open full text
  • On the degree correlation of urban road networks.
    Jing Tian, Huaqiang Fang, Yiheng Wang, Chang Ren.
    Transactions in GIS. October 17, 2017
    Recent advances in network science and the development of volunteered geographic information (VGI) have created new research opportunities in the topological analysis of road networks. The degree correlation of road networks is rarely studied. This study applied four measures, including the average degree of nearest neighbor, correlation profile, Newman's assortativity coefficient, and Litvak–Hofstad's assortativity coefficient, to measure the degree correlations of road networks represented as dual graphs of strokes, axial lines, and named roads. After investigating 100 road networks worldwide obtained from OpenStreetMap, it has been found that road networks are mostly disassortative or uncorrelated in stroke and named road representations, but assortative when represented as axial lines. Inconsistency in different measures persists regardless of method of representation; therefore, qualitative dichotomy or trichotomy is insufficient to describe the actual connection pattern in road networks. A taxonomy of road network assortativity is proposed. Two of the proposed disassortative types are associated with the absence of a grid pattern and are less robust than the typical disassortative type.
    October 17, 2017   doi: 10.1111/tgis.12299   open full text
  • Morphology‐based modeling of aggregation effect on the patch area size for GlobeLand30 data.
    Shiteng Tan, Zhu Xu, Peng Ti, Zhilin Li.
    Transactions in GIS. October 10, 2017
    Currently, research on the scale effect mainly concentrates on revealing and describing the phenomenon; little work has been done to model the scaling of analysis indicators along with the scale change of the data. Such models can help explain and estimate the scale effect and are thus of great interest. As patch morphology significantly influences patch evolution over data scale transformation, this study proposes a model that applies patch morphology metrics to explain and estimate the change in the patch and category area ratio in the upscaling of raster categorical data. In the experimental evaluation, area scaling of GlobeLand30 data under majority aggregation is studied intensively. Two metrics—the ratio of the patch area after aggregation to its original area and the ratio of the category area after aggregation to its original area—are used in this evaluation. The experimental results indicate that this model can adequately describe the pattern of the patch area change and precisely estimate the category area change arising from the resolution change. It is also demonstrated that the spatial distribution of patches has much less influence on the change in the category areas compared with the patch morphology. Additionally, the modeling approach in this study may also be adopted to investigate the scaling of other landscape metrics.
    October 10, 2017   doi: 10.1111/tgis.12298   open full text
  • An enhanced approach for surface flow routing over drainage‐constrained triangulated irregular networks.
    Fangli Zhang, Qiming Zhou, Qingquan Li, Guofeng Wu, Jun Liu.
    Transactions in GIS. September 21, 2017
    The accuracy and efficiency of the simulations in distributed hydrological models must depend on the proper estimation of flow directions and paths. Numerous studies have been carried out to delineate the drainage patterns based on gridded digital elevation models (DEMs). The triangulated irregular network (TIN) has been increasingly applied in hydrological applications due to the advantages of high storage efficiency and multi‐scale adaptive performance. Much of the previous literature focuses mainly on filling the depressions on gridded DEMs rather than treating the special cases in TIN structures, which has hampered its applications to hydrological models. This study proposes a triangulation‐based solution for the removal of flat areas and pits to enhance the simulation of flow routing on triangulated facet networks. Based on the drainage‐constrained TIN generated from only a gridded DEM by the compound point extraction (CPE) method, the inconsistent situations including flat triangles, V‐shape flat edges and sink nodes are respectively identified and rectified. The optimization algorithm is an iterative process of TIN reconstruction, in which the flat areas are generalized into their center points and the pits are rectified by embedding break lines. To verify the proposed algorithm and investigate the potential for flow routing, flow paths of steepest descent are derived by the vector‐based tracking algorithm based on the optimized TIN. A case study of TIN optimization and flow path tracking was performed on a real‐world DEM. The outcomes indicate that the proposed approach can effectively solve the problem of inconsistencies without a significant loss in accuracy of the terrain model.
    September 21, 2017   doi: 10.1111/tgis.12294   open full text
  • Northern marine transportation corridors: Creation and analysis of northern marine traffic routes in Canadian waters.
    René Chénier, Loretta Abado, Olivier Sabourin, Laurent Tardif.
    Transactions in GIS. September 21, 2017
    The concept of the Northern Marine Transportation Corridors (NMTC) initiative was developed under the Government of Canada World‐Class Tanker Safety System Initiative (WCTSS). The NMTC is an interdepartmental Arctic initiative within the Department of Fisheries and Oceans Canada (DFO), through the Canadian Coast Guard (CCG) and the Canadian Hydrographic Service (CHS), in collaboration with Transport Canada (TC). The NMTC initiative was developed to strengthen the safety of marine navigation in the Arctic, and to offer an efficient planning guide for present and future Arctic investments. Transportation corridors identified through this initiative will provide the Government of Canada the framework needed to better prioritize and deliver on its programs and services, including: nautical charts and products; aids to navigation; icebreaking services; and marine safety regulations. The corridors were generated and analyzed with a Geographic Information System (GIS) using two main data sources: the Automated Identification System (AIS) and CHS's nautical charts and publications. The geographic extent of the NMTC is defined as the Northern Canada Vessel Traffic Service Zone (NORDREG Zone) and the Mackenzie River. With close to 4 million km2 of water in the Arctic and 162,000 km of coastline, surveying the Arctic to modern standards represents an enormous challenge to CHS. By adopting a corridor‐based approach, CHS and other government programs can prioritize their efforts on 12% of the Canadian Arctic waters. CHS currently has 32% of the NMTC adequately surveyed, with an additional 3% surveyed to modern standards.
    September 21, 2017   doi: 10.1111/tgis.12295   open full text
  • Inferring the home locations of Twitter users based on the spatiotemporal clustering of Twitter data.
    Jie Lin, Robert G. Cromley.
    Transactions in GIS. September 21, 2017
    Residential locations play an important role in understanding the form and function of urban systems. However, it is impossible to release this detailed information publicly, due to the issue of privacy. The rapid development of location‐based services and the prevalence of global position system (GPS)‐equipped devices provide an unprecedented opportunity to infer residential locations from user‐generated geographic information. This article compares different approaches for predicting Twitter users' home locations at a precise point level based on temporal and spatial features extracted from geo‐tagged tweets. Among the three deterministic approaches, the one that estimates the home location for each user by finding the weighted most frequently visited (WMFV) cluster of that user always provides the best performance when compared with the other two methods. The results of a fourth approach, based on the support vector machine (SVM), are severely affected by the threshold value for a cluster to be identified as the home.
    September 21, 2017   doi: 10.1111/tgis.12297   open full text
  • Validity of historical volunteered geographic information: Evaluating citizen data for mapping historical geographic phenomena.
    Guiming Zhang, A‐Xing Zhu, Zhi‐Pang Huang, Guopeng Ren, Cheng‐Zhi Qin, Wen Xiao.
    Transactions in GIS. September 21, 2017
    Studies on volunteered geographic information (VGI) have focused on examining its validity to reveal geographic phenomena in relatively recent periods. Empirical evaluation of the validity of VGI to reveal geographic phenomena in historical periods (e.g., decades ago) is lacking, although such evaluation is desirable for assessing the possibility of broadening the temporal scope of VGI applications. This article presents an evaluation of the validity of VGI to reveal historical geographic phenomena through a citizen data‐based habitat suitability mapping case study. Citizen data (i.e., sightings) of the black‐and‐white snub‐nosed monkey (Rhinopithecus bieti) were elicited from local residents through three‐dimensional (3D) geovisualization interviews in Yunnan, China. The validity of the elicited sightings to reveal the historical R. bieti distribution was evaluated through habitat suitability mapping using the citizen data in historical periods. The results of controlled experiments demonstrated that suitability maps predicted using the historical citizen data had a consistent spatial pattern (correlation above 0.60) that reflects the R. bieti distribution (Boyce index around 0.90) in areas free of significant environmental change across historical periods. This in turn suggests that citizen data have validity for mapping historical geographic phenomena. It provides supporting empirical evidence for potentially broadening the temporal scope of VGI applications.
    September 21, 2017   doi: 10.1111/tgis.12300   open full text
  • Geomorphometry from unmanned aerial surveys.
    Igor V. Florinsky, Vladimir M. Kurkov, Dmitrii P. Bliakharskii.
    Transactions in GIS. September 20, 2017
    Unmanned aerial systems (UASs) are widely used for remote sensing, including the production of high‐resolution digital elevation models (DEMs). We study the possibilities of UAS‐based aerial surveys to produce photogrammetrically sound, high‐resolution DEMs intended for geomorphometric modeling. The study was conducted at the Zaoksky testing ground (Russia). To carry out an aerial survey, we used a UAS Geoscan‐101 equipped with a Sony DSC‐RX1 camera and a Topcon GNSS receiver. Aerial photographs were processed using Agisoft PhotoScan Professional software. Applying dense point cloud generation and classification, we produced DEMs with resolutions of 6 cm, 20 cm, and 1 m. Using a universal spectral analytical method, we derived models of several morphometric variables (i.e., slope gradient, horizontal, vertical, minimal, and maximal curvatures) from DEMs with resolutions of 20 cm and 1 m. We found that it is possible to produce noiseless models and well‐readable maps of morphometric variables for grassy areas with separately standing groups of trees and shrubs. However, UAS‐based DEMs cannot be applied for modeling of forested areas: there occur pronounced unrecoverable artifacts due to errors of automated classification of the dense point cloud. Finally, we present recommendations for the production of UAS‐derived, photogrammetrically sound, high‐resolution DEMs intended for geomorphometry.
    September 20, 2017   doi: 10.1111/tgis.12296   open full text
  • Extending F‐Perceptory to model fuzzy objects with composite geometries for GIS.
    Besma Khalfi, Cyril De Runz, Sami Faiz, Herman Akdag.
    Transactions in GIS. August 14, 2017
    When analyzing spatial issues, geographers are often confronted with many problems with regard to the imprecision of the available information. It is necessary to develop representation and design methods which are suited to imprecise spatiotemporal data. This led to the recent proposal of the F‐Perceptory approach. F‐Perceptory models fuzzy primitive geometries that are appropriate in representing homogeneous regions. However, the real world often contains cases that are much more complex, describing geographic features with composite structures such as a geometry aggregation or combination. From a conceptual point of view, these cases have not yet been managed with F‐Perceptory. This article proposes modeling fuzzy geographic objects with composite geometries, by extending the pictographic language of F‐Perceptory and its mapping to the Unified Modeling Language (UML) necessary to manage them in object/relational databases. Until now, the most commonly used object modeling tools have not considered imprecise data. The extended F‐Perceptory is implemented under a UML‐based modeling tool in order to support users in fuzzy conceptual data modeling. In addition, in order to properly define the related database design, an automatic derivation process is implemented to generate the fuzzy database model.
    August 14, 2017   doi: 10.1111/tgis.12290   open full text
  • GEN_MAT: A MATLAB‐based map generalization algorithm toolbox.
    Yiheng Wang, Jing Tian, Mengting Yu, Chang Ren, Xiaohuan Wu.
    Transactions in GIS. August 13, 2017
    Assistive tools are important for improving teaching and learning quality in courses that involve practical work. This article presents an overview of GEN_MAT, the first MATLAB‐based map generalization algorithm toolbox. The toolbox provides 42 map generalization algorithms for aggregation, selective omission, simplification, smoothing, collapse, agglomeration, merging, dissolving, displacement, and typification. A beta test of the application of GEN_MAT in teaching and learning was conducted. Evaluations showed that GEN_MAT has positive effects on teaching and learning. Comparing tool‐based and non‐tool‐based courses indicated that the experimental group performed better than the control group, and the two groups exhibited significant discrepancy (p < 0.05) in confidence, awareness, skills and attitudes or behaviors.
    August 13, 2017   doi: 10.1111/tgis.12291   open full text
  • A new generation of Primary Care Service Areas or general practice catchment areas.
    Soumya Mazumdar, Ludovico Pinzari, Nasser Bagheri, Paul Konings, Federico Girosi, Ian Mcrae.
    Transactions in GIS. August 07, 2017
    Primary Care is fundamental to a well‐functioning health system. Various geographical small areas including specialized geographies such as Primary Care Service Areas (PCSAs) are used to measure primary care relevant outcomes and services, or to target interventions. PCSAs are small areas, the majority of patients resident in which obtain their primary care services from within the geography. The extent of this self‐sufficiency of use is measured by the Localization Index (LI). PCSAs have been built in the US, Australia and Switzerland using an allocation algorithm, which, while simple and easy to implement, may require the use of various ad‐hoc parameters. In this article we propose an optimization based approach to creating PCSAs, ‐ an approach which has previously been used to generate labour flow regions in Ireland. The approach is data driven, thus requiring a minimal number of ad‐hoc parameters. We compared the resulting PCSAs (or `rPCSAs') with PCSAs generated using the traditional allocation algorithm. We found that rPCSAs were generally larger, offered greater LIs and reflected patient travel patterns better than traditional PCSAs. Accounting for the larger size of rPCSAs showed that rPCSAs offered better LIs than similar sized traditional PCSAs.
    August 07, 2017   doi: 10.1111/tgis.12287   open full text
  • An analysis of movement patterns between zones using taxi GPS data.
    Zhanlong Chen, Xi Gong, Zhong Xie.
    Transactions in GIS. August 07, 2017
    The discovery of zones and people's movement patterns supports a better understanding of modern cities and enables a more comprehensive strategy for urban planning. This article proposes a modified method based on previous research to simultaneously discover people's zones and movement patterns, called movement patterns between functional zones (MPFZ). The method attempts to take full advantage of taxi GPS data to identify MPFZs by merging the movement traces satisfying the merging conditions. Considering movement directions, movement numbers and the adjacent constraints that consist of spatial relationship and attribute features, the merging conditions limit the movement traces to be merged. The new MPFZs are discovered by an iteration process and are measured by the following three evaluation indices: v‐value, a‐value and c‐value, which represent coverage, accuracy and their trade‐off. Using a real‐world taxi dataset of Beijing, 24 new MPFZs are discovered, which have higher v‐, a‐ and c‐values than the unmerged MPFZs. The results of the real‐world dataset experiment show that the proposed approach is effective and efficient. The proposed method can also be applied to other types of transportation data and regions by adjusting the dataset utilized and controlling the iteration process.
    August 07, 2017   doi: 10.1111/tgis.12281   open full text
  • Modelling future impacts of urban development in Kuwait with the use of ABM and GIS.
    Nayef Alghais, David Pullar.
    Transactions in GIS. August 01, 2017
    During the last six decades, Kuwait has experienced rapid and unprecedented population growth with only a small increase in the urban areas. The alarming rise in urban density in Kuwait has caused issues for the residents' lifestyles, the economy and the environment. These issues have been aggravated by urban planning which perpetuated a city‐centric urban form without modelling the impacts of current patterns of urban growth. A spatial model using Agent Based Modelling (ABM) and Geographical Information Systems (GIS) is proposed to model disaggregate future changes in land‐use patterns given forecast population estimates and planning policies. The two main impacts considered are housing shortage and traffic congestion, as these are the two most significant social impacts for Kuwaitis. This article discusses the design methodology and parameterization of the ABM and the agent groups. It characterizes urban growth by rules for different citizen groups, historical growth patterns and the influence of decision‐makers. The model is validated against data for the period 1995‐2015 and simulations run to 2050; the results predict that continued city‐centric growth will aggravate the problems, with more than 50% increase in housing shortage and congestion unless the government intervenes to rectify the situation.
    August 01, 2017   doi: 10.1111/tgis.12293   open full text
  • A multi‐label cellular automata model for land change simulation.
    Omar Charif, Hichem Omrani, Fahed Abdallah, Bryan Pijanowski.
    Transactions in GIS. August 01, 2017
    The use of cellular automata (CA) has for some time been considered among the most appropriate approaches for modeling land‐use changes. Each cell in a traditional CA model has a state that evolves according to transition rules, taking into consideration its own and its neighbors’ states and characteristics. Here, we present a multi‐label CA model in which a cell may simultaneously have more than one state. The model uses a multi‐label learning method—a multi‐label support vector machine, Rank‐SVM—to define the transition rules. The model was used with a multi‐label land‐use dataset for Luxembourg, built from vector‐based land‐use data using a method presented here. The proposed multi‐label CA model showed promising performance in terms of its ability to capture and model the details and complexities of changes in land‐use patterns. Applied to historical land use data, the proposed model estimated the land use change with an accuracy of 87.2% exact matching and 98.84% when including cells with a misclassification of a single label, which is comparably better than a classical multi‐class model that achieved 83.6%. The multi‐label cellular automata outperformed a model combining CA and artificial neural networks. All model goodness‐of‐fit comparisons were quantified using various performance metrics for predictive models.
    August 01, 2017   doi: 10.1111/tgis.12279   open full text
  • Improving urban cellular automata performance by integrating global and geographically weighted logistic regression models.
    Babak Mirbagheri, Abbas Alimohammadi.
    Transactions in GIS. July 31, 2017
    In many of the conventional cellular automata (CA) models, particularly Urban‐CA which are used for urban growth, the spatial heterogeneities and local differences of the land use conversion processes are ignored. Global logistic regression (LR) is a popular model employed to define the transition rules of Urban‐CA. By considering the local characteristics, Geographically Weighted Logistic Regression (GWLR) provides interesting capabilities for urban growth modelling. In this research, in addition to using GWLR in the definition of transition rules, the advantages of integrating GWLR and LR for urban growth simulation were evaluated; these have not been considered in previous studies. Local and global probabilities obtained from the calibration of GWLR and LR were combined to define the transition rules of an Urban‐CA. Urban growth was simulated in the Islamshahr sub‐region located southwest of Tehran, Iran for the two periods 1992‐1996 and 1996‐2002, and data from these periods were used for training and testing the prediction abilities, respectively. In the first period, GWLR showed good performance and a significant contribution to the enhancement of the simulation performance, but in the second period, the effectiveness of LR on the prediction accuracy increased. Due to their complementary roles, the integration of the GWLR and LR models resulted in improved simulation performance in both periods.
    July 31, 2017   doi: 10.1111/tgis.12278   open full text
  • Urban event detection with big data of taxi OD trips: A time series decomposition approach.
    Xi Zhu, Diansheng Guo.
    Transactions in GIS. June 23, 2017
    Big urban mobility data, such as taxi trips, cell phone records, and geo‐social media check‐ins, offer great opportunities for analyzing the dynamics, events, and spatiotemporal trends of the urban social landscape. In this article, we present a new approach to the detection of urban events based on location‐specific time series decomposition and outlier detection. The approach first extracts long‐term temporal trends and seasonal periodicity patterns. Events are defined as anomalies that deviate significantly from the prediction with the discovered temporal patterns, i.e., trend and periodicity. Specifically, we adopt the STL approach, i.e., seasonal and trend decomposition using LOESS (locally weighted scatterplot smoothing), to decompose the time series for each location into three components: long‐term trend, seasonal periodicity, and the remainder. Events are extracted from the remainder component for each location with an outlier detection method. We analyze over a billion taxi trips for over seven years in Manhattan (New York City) to detect and map urban events at different temporal resolutions. Results show that the approach is effective and robust in detecting events and revealing urban dynamics with both holistic understandings and location‐specific interpretations.
    June 23, 2017   doi: 10.1111/tgis.12288   open full text
  • Terra Populus’ architecture for integrated big geospatial services.
    David Haynes, Steve Manson, Eric Shook.
    Transactions in GIS. June 23, 2017
    Big geospatial data is an emerging sub‐area of geographic information science, big data, and cyberinfrastructure. Big geospatial data poses two unique challenges. First, raster and vector data structures and analyses have developed on largely separate paths for the last 20 years. This is creating an impediment to geospatial researchers seeking to utilize big data platforms that do not promote heterogeneous data types. Second, big spatial data repositories have yet to be integrated with big data computation platforms in ways that allow researchers to spatio‐temporally analyze big geospatial datasets. IPUMS‐Terra, a National Science Foundation cyberInfrastructure project, addresses these challenges by providing a unified framework of integrated geospatial services which access, analyze, and transform big heterogeneous spatio‐temporal data. As IPUMS‐Terra's data volume grows, we seek to integrate geospatial platforms that will scale geospatial analyses and address current bottlenecks within our system. However, our work shows that there are still unresolved challenges for big geospatial analysis. The most pertinent is that there is a lack of a unified framework for conducting scalable integrated vector and raster data analysis. We conducted a comparative analysis between PostgreSQL with PostGIS and SciDB and concluded that SciDB is the superior platform for scalable raster zonal analyses.
    June 23, 2017   doi: 10.1111/tgis.12286   open full text
  • Extracting central places from the link structure in Wikipedia.
    Carsten Keßler.
    Transactions in GIS. June 23, 2017
    Explicit information about places is captured in an increasing number of geospatial datasets. This article presents evidence that relationships between places can also be captured implicitly. It demonstrates that the hierarchy of central places in Germany is reflected in the link structure of the German language edition of Wikipedia. The official upper and middle centers declared, based on German spatial laws, are used as a reference dataset. The characteristics of the link structure around their Wikipedia pages, which link to each other or mention each other, and how often, are used to develop a bottom‐up method for extracting central places from Wikipedia. The method relies solely on the structure and number of links and mentions between the corresponding Wikipedia pages; no spatial information is used in the extraction process. The output of this method shows significant overlap with the official central place structure, especially for the upper centers. The results indicate that real‐world relationships are in fact reflected in the link structure on the web in the case of Wikipedia.
    June 23, 2017   doi: 10.1111/tgis.12284   open full text
  • How friends share urban space: An exploratory spatiotemporal analysis using mobile phone data.
    Yang Xu, Alexander Belyi, Iva Bojic, Carlo Ratti.
    Transactions in GIS. June 23, 2017
    This study proposes a framework to investigate the roles of urban spaces in connecting social contacts (i.e., “friends”). The framework is applied to a Call Detail Record (CDR) dataset collected in Singapore. First, a comparative analysis is performed to understand how friends share urban space differently from random people. Then, we derive two metrics to quantify the “bonding” and “bridging” capabilities of places in the city. The two metrics reflect the potential of a place in connecting friends and random people (e.g., chance encounters), respectively. Finally, we examine the temporal signature of the places’ bonding capabilities, and associate the results with various types of Points of Interest (POIs). We find that: (1) friends are more likely to share urban space than random people, and they also share more locations; (2) a place could play different roles in connecting friends vs. random people, and the relationship (between bonding and bridging) varies depending on the time and type of a day (weekdays vs. weekends); (3) the temporal signature of bonding capability is strongly related to the semantics of a place; (4) certain POI types (e.g., shopping malls) tend to have a much higher impact on bonding capability than others (e.g., sports centers).
    June 23, 2017   doi: 10.1111/tgis.12285   open full text
  • Extracting urban functional regions from points of interest and human activities on location‐based social networks.
    Song Gao, Krzysztof Janowicz, Helen Couclelis.
    Transactions in GIS. June 23, 2017
    Data about points of interest (POI) have been widely used in studying urban land use types and for sensing human behavior. However, it is difficult to quantify the correct mix or the spatial relations among different POI types indicative of specific urban functions. In this research, we develop a statistical framework to help discover semantically meaningful topics and functional regions based on the co‐occurrence patterns of POI types. The framework applies the latent Dirichlet allocation (LDA) topic modeling technique and incorporates user check‐in activities on location‐based social networks. Using a large corpus of about 100,000 Foursquare venues and user check‐in behavior in the 10 most populated urban areas of the US, we demonstrate the effectiveness of our proposed methodology by identifying distinctive types of latent topics and, further, by extracting urban functional regions using K‐means clustering and Delaunay triangulation spatial constraints clustering. We show that a region can support multiple functions but with different probabilities, while the same type of functional region can span multiple geographically non‐adjacent locations. Since each region can be modeled as a vector consisting of multinomial topic distributions, similar regions with regard to their thematic topic signatures can be identified. Compared with remote sensing images which mainly uncover the physical landscape of urban environments, our popularity‐based POI topic modeling approach can be seen as a complementary social sensing view on urban space based on human activities.
    June 23, 2017   doi: 10.1111/tgis.12289   open full text
  • The Cost(s) of Geospatial Open Data.
    Peter A. Johnson, Renee Sieber, Teresa Scassa, Monica Stephens, Pamela Robinson.
    Transactions in GIS. June 23, 2017
    The provision of open data by governments at all levels has rapidly increased over recent years. Given that one of the dominant motivations for the provision of open data is to generate ‘value’, both economic and civic, there are valid concerns over the costs incurred in this pursuit. Typically, costs of open data are framed as internal to the data providing government. Building on the strong history of GIScience research on data provision via spatial data infrastructures, this article considers both the direct and indirect costs of open data provision, framing four main areas of indirect costs: citizen participation challenges, uneven provision across geography and user types, subsidy of private sector activities, and the creation of inroads for corporate influence on government. These areas of indirect cost lead to the development of critical questions, including constituency, purpose, enablement, protection, and priorities. These questions are posed as a guide to governments that provide open data in addressing the indirect costs of open data.
    June 23, 2017   doi: 10.1111/tgis.12283   open full text
  • The interaction between individual, social and environmental factors and their influence on dietary intake among adults in Toronto.
    Daniel Liadsky, Brian Ceh.
    Transactions in GIS. June 12, 2017
    Health outcomes related to vegetable and fruit consumption are widely recognized in the literature. This study investigates how dietary intake is influenced by individual, social, and environmental factors in the Toronto Census Metropolitan Area. The analysis and findings are based on data from the Canadian Community Health Survey which provides self‐reported vegetable and fruit intake from 6,513 adults in 2009‐2010. Food environment measures were constructed from commercial databases using kernel density estimates and network drive times. Spatial and multivariable techniques were used to determine the associations between diet, the food environment, and other health and socioeconomic factors. Particular emphasis was given to understanding the interaction between the food environment and socioeconomic position. Unexpectedly, supermarket density was found to have an inverse association with vegetable and fruit intake. Interaction terms for individuals with low income and reduced mobility produced different responses in men and women, confirming that the influence of the food environment is not uniform for all subgroups.
    June 12, 2017   doi: 10.1111/tgis.12276   open full text
  • Place and city: Operationalizing sense of place and social capital in the urban context.
    Albert Acedo, Marco Painho, Sven Casteleyn.
    Transactions in GIS. June 09, 2017
    The academic interest in social concepts in city contexts, such as sense of place and social capital, has been growing in the last decades. We present a systematic literature review that confirms the strong relationship between sense of place and social capital, from a social sciences point‐of‐view. It also reveal that little attention has been paid to their spatial dimensions at the urban level, thereby missing the chance to exploit socio‐spatial knowledge to improve the day‐to‐day life in and functioning of the city (e.g. in planning processes, citizen participation, civic engagement). We therefore examine sense of place and social capital from a Geographic Information Science (GISc) viewpoint, and present a formal conceptualization and initial theoretical framework which explicitly describes both concepts, and the relation between them, within the context of a city and from a spatial point of view.
    June 09, 2017   doi: 10.1111/tgis.12282   open full text
  • Extracting spatial patterns in bicycle routes from crowdsourced data.
    Jody Sultan, Gev Ben‐Haim, Jan‐Henrik Haunert, Sagi Dalyot.
    Transactions in GIS. June 06, 2017
    Much is done nowadays to provide cyclists with safe and sustainable road infrastructure. Its development requires the investigation of road usage and interactions between traffic commuters. This article is focused on exploiting crowdsourced user‐generated data, namely GPS trajectories collected by cyclists and road network infrastructure generated by citizens, to extract and analyze spatial patterns and road‐type use of cyclists in urban environments. Since user‐generated data shows data‐deficiencies, we introduce tailored spatial data‐handling processes for which several algorithms are developed and implemented. These include data filtering and segmentation, map‐matching and spatial arrangement of GPS trajectories with the road network. A spatial analysis and a characterization of road‐type use are then carried out to investigate and identify specific spatial patterns of cycle routes. The proposed analysis was applied to the cities of Amsterdam (The Netherlands) and Osnabrück (Germany), proving its feasibility and reliability in mining road‐type use and extracting pattern information and preferences. This information can help users who wish to explore friendlier and more interesting cycle patterns, based on collective usage, as well as city planners and transportation experts wishing to pinpoint areas most in need of further development and planning.
    June 06, 2017   doi: 10.1111/tgis.12280   open full text
  • An efficient data organization and scheduling strategy for accelerating large vector data rendering.
    Mingqiang Guo, Ying Huang, Qingfeng Guan, Zhong Xie, Liang Wu.
    Transactions in GIS. May 23, 2017
    Rendering large volumes of vector data is computationally intensive and therefore time consuming, leading to lower efficiency and poorer interactive experience. Graphics processing units (GPUs) are powerful tools in data parallel processing but lie idle most of the time. In this study, we propose an approach to improve the performance of vector data rendering by using the parallel computing capability of many‐core GPUs. Vertex transformation, largely a mathematical calculation that does not require communication with the host storage device, is a time‐consuming procedure because all coordinates of each vector feature need to be transformed to screen vertices. Use of a GPU enables optimization of a general‐purpose mathematical calculation, enabling the procedure to be executed in parallel on a many‐core GPU and optimized effectively. This study mainly focuses on: (1) an organization and storage strategy for vector data based on equal pitch alignment, which can adapt to the GPU's calculating characteristics; (2) a paging‐coalescing transfer and memory access strategy for vector data between the CPU and the GPU; and (3) a balancing allocation strategy to take full advantage of all processing cores of the GPU. Experimental results demonstrate that the approach proposed can significantly improve the efficiency of vector data rendering.
    May 23, 2017   doi: 10.1111/tgis.12275   open full text
  • Gully boundary extraction based on multidirectional hill‐shading from high‐resolution DEMs.
    Xin Yang, Min Li, Jiaming Na, Kai Liu.
    Transactions in GIS. May 23, 2017
    The gully boundary, which distinguishes gully from non‐gully areas, is a significant geomorphologic feature for research on gully development and gully erosion. This study presents a new method based on multidirectional hill‐shading maps, which identify the gully (i.e., shadow area) from inter‐gully (i.e., non‐shadow area). These shadows obtained from various illumination azimuths are merged; consequently, the border of the shadows, which is the gully boundary line, can be achieved. In this process, two key parameters, namely, altitude and azimuth of light, affect the accuracy of gully boundary extraction. The experiments in Yaojiawan area of China show that the method of average median slope of all sampling profiles across the gully boundary is effective and practical for light altitude selection. Moreover, the six azimuths are sufficient for gully boundary extraction in a loess hilly area. The application in the Madigou area indicates the replicability and rationality of this method. A comparison with the positive‐negative terrain and slope variation method confirms a higher accuracy of gully boundary extraction by the proposed method in terms of visual interpretation, length, and contour‐matching difference with reference to manually digitalized results. Accuracy assessment indicates that the proposed method is applicable for gully boundary extraction based on high‐resolution DEMs.
    May 23, 2017   doi: 10.1111/tgis.12273   open full text
  • Mentoring undergraduates in cartography and geographic information science: An apprenticeship model.
    Jing Tian.
    Transactions in GIS. May 23, 2017
    Undergraduates' participation in research has been demonstrated to contribute to the development of critical, technical thinking and problem‐solving skills, increase confidence, and enhance interest in research and graduate studies. For fields like cartography and geographic information science (GIS), teaching content should be up‐to‐date. Furthermore, practice plays a key role in daily teaching and learning. Therefore, research participation is of great significance for undergraduates majoring in cartography and GIS. Here a mentoring method is proposed for undergraduates, based on the apprenticeship model which combines mentoring functions and styles. Thirty‐one undergraduates were mentored using the method. An evaluation based on objective outcomes and subjective self‐perceptions showed that the mentoring method was effective: 71% of the subjects contributed to at least one peer‐reviewed paper or software program. Possible factors affecting the mentoring results include the length of time the undergraduates were involved in mentorship and engaged in research. The longer the undergraduates participated in the mentorship and the more time they spent on research, the more numerous their achievements. Participants demonstrated significant improvements in the following areas: Changes in attitudes toward learning and research, enhanced career/graduate school preparation and personal gains. Significant differences in “learning ethical conduct” and “professional skills” were observed between genders.
    May 23, 2017   doi: 10.1111/tgis.12272   open full text
  • A GIS‐based multi‐criteria seismic vulnerability assessment using the integration of granular computing rule extraction and artificial neural networks.
    Hossein Sheikhian, Mahmoud Reza Delavar, Alfred Stein.
    Transactions in GIS. May 14, 2017
    This study proposes multi‐criteria group decision‐making to address seismic physical vulnerability assessment. Granular computing rule extraction is combined with a feed forward artificial neural network to form a classifier capable of training a neural network on the basis of the rules provided by granular computing. It provides a transparent structure despite the traditional multi‐layer neural networks. It also allows the classifier to be applied on a set of rules for each incoming pattern. Drawbacks of original granular computing (GrC) are covered, where some input patterns remained unclassified. The study was applied to classify seismic vulnerability of the statistical units of the city of Tehran, Iran. Slope, seismic intensity, height and age of the buildings were effective parameters. Experts ranked 150 randomly selected sample statistical units with respect to their degree of seismic physical vulnerability. Inconsistency of the experts' judgments was investigated using the induced ordered weighted averaging (IOWA) operator. Fifty‐five classification rules were extracted on which a neural network was based. An overall accuracy of 88%, κ = 0.85 and R2 = 0.89 was achieved. A comparison with previously implemented methodologies proved the proposed method to be the most accurate solution to the seismic physical vulnerability of Tehran.
    May 14, 2017   doi: 10.1111/tgis.12274   open full text
  • A new dynamic network flow algorithm using base state amendment model for emergency response.
    Jincheng Jiang, Lixin Wu.
    Transactions in GIS. May 11, 2017
    Large‐scale earthquake disasters in recent years have caused huge damage to people's lives and property. Quick effective emergency response is the primary task post‐disaster. A dynamic network flow model can be used to obtain an effective emergency material rescue plan for the transportation network. Strong timeliness is a critical factor to emergency response. However, very few efficient algorithms were presented for most dynamic network flow problems. To solve this issue, this article introduces a novel low‐time‐complexity exact algorithm using the continuous‐time dynamic network flow (CTDNF) and the base state with amendment (BSA) model in the geographic information science field. Besides, this new CTDNF‐BSA algorithm is improved to solve more complex cases with dynamic capacity and transmit time in a dynamic transportation network. Both numerical and geographic experiments were conducted to assess the correctness, time and space performance of the presented CTDNF‐BSA algorithm. The experimental results demonstrated that the CTDNF‐BSA algorithm can attain the optimal solution with good computing time and space performance as compared with traditional algorithms. Geographic cases in dynamic situations for real emergency response illustrated that the CTDNF‐BSA algorithm can provide effective decision support for emergency material rescue planning in a dynamic transportation environment.
    May 11, 2017   doi: 10.1111/tgis.12271   open full text
  • Two‐dimensional discrete Fourier transform analysis of karst and coral reef morphologies.
    Jerry D. Davis, Joseph D. Chojnacki.
    Transactions in GIS. May 03, 2017
    Fourier transforms have been used in the analysis of landscapes that exhibit the influence of cyclic structures or other morphogenetic controls. Two‐dimensional Fourier transforms have been most successful when modeling features with a high frequency over the sample space. This research focuses on applications of 2D discrete Fourier transforms for karst and spur and groove coral reefs, using ArcGIS geoprocessing tools extended with Python NumPy numerical methods. Ten‐meter digital elevation data from Puerto Rico and Kentucky holokarst landscapes and five‐meter bathymetry from more unidirectional spur and groove coral reefs at Midway Atoll were analyzed. Our method identifies the dominant contributing waves in frequency space, and analyzed power contributions by 5° and 15° azimuth bins. A limiting factor in this analysis is the spatial extent of consistent morphology in the landscape. In contrast to time‐domain Fourier analysis, dominant landform frequencies can thus be of low magnitude, creating an imprecise estimate of wave morphometry and direction since this is derived from the combination of inverted x and y frequency values, and the limited frequency grain inherent in the discrete model degrades precision in the solution. Simulated karst and spur & groove landscapes were used to evaluate the grain of waveform orientation solutions.
    May 03, 2017   doi: 10.1111/tgis.12277   open full text
  • An effective ensemble classification framework using random forests and a correlation based feature selection technique.
    Dibyajyoti Chutia, Dhruba Kumar Bhattacharyya, Jaganath Sarma, Penumetcha Narasa Lakshmi Raju.
    Transactions in GIS. April 27, 2017
    Accurate classification of heterogeneous land surfaces with homogeneous land cover classes is a challenging task as satellite images are characterized by a large number of features in the spectral and spatial domains. The identifying relevance of a feature or feature set is an important task for designing an effective classification scheme. Here, an ensemble of random forests (RF) classifiers is realized on the basis of relevance of features. Correlation‐based Feature Selection (CFS) was utilized to assess the relevance of a subset of features by studying the individual predictive ability of each feature along with the degree of redundancy between them. Predictability of RF was greatly improved by random selection of the relevant features in each of the splits. An investigation was carried out on different types of images from the Landsat Enhanced Thematic Mapper Plus (Landsat ETM+) and QuickBird sensors. It has been observed that the performance of the RF classifier was significantly improved while using the optimal set of relevant features compared with a few of the most advanced supervised classifiers such as maximum likelihood classifier (MLC), Navie Bayes, multi‐layer perception (MLP), support vector machine (SVM) and bagging.
    April 27, 2017   doi: 10.1111/tgis.12268   open full text
  • Modeling global Hammond landform regions from 250‐m elevation data.
    Deniz Karagulle, Charlie Frye, Roger Sayre, Sean Breyer, Peter Aniello, Randy Vaughan, Dawn Wright.
    Transactions in GIS. March 12, 2017
    In 1964, E.H. Hammond proposed criteria for classifying and mapping physiographic regions of the United States. Hammond produced a map entitled “Classes of Land Surface Form in the Forty‐Eight States, USA”, which is regarded as a pioneering and rigorous treatment of regional physiography. Several researchers automated Hammond?s model in GIS. However, these were local or regional in application, and resulted in inadequate characterization of tablelands. We used a global 250 m DEM to produce a new characterization of global Hammond landform regions. The improved algorithm we developed for the regional landform modeling: (1) incorporated a profile parameter for the delineation of tablelands; (2) accommodated negative elevation data values; (3) allowed neighborhood analysis window (NAW) size to vary between parameters; (4) more accurately bounded plains regions; and (5) mapped landform regions as opposed to discrete landform features. The new global Hammond landform regions product builds on an existing global Hammond landform features product developed by the U.S. Geological Survey, which, while globally comprehensive, did not include tablelands, used a fixed NAW size, and essentially classified pixels rather than regions. Our algorithm also permits the disaggregation of “mixed” Hammond types (e.g. plains with high mountains) into their component parts.
    March 12, 2017   doi: 10.1111/tgis.12265   open full text
  • A spatial parallel heuristic approach for solving very large‐scale vehicle routing problems.
    Wei Tu, Qingquan Li, Qiuping Li, Jiasong Zhu, Baoding Zhou, Biyu Chen.
    Transactions in GIS. March 10, 2017
    The vehicle routing problem (VRP) is one of the most prominent problems in spatial optimization because of its broad applications in both the public and private sectors. This article presents a novel spatial parallel heuristic approach for solving large‐scale VRPs with capacity constraints. A spatial partitioning strategy is devised to divide a region of interest into a set of small spatial cells to allow the use of a parallel local search with a spatial neighbor reduction strategy. An additional local search and perturbation mechanism around the border area of spatial cells is used to improve route segments across spatial cells to overcome the border effect. The results of one man‐made VRP benchmark and three real‐world super‐large‐scale VRP instances with tens of thousands of nodes verify that the presented spatial parallel heuristic approach achieves a comparable solution with much less computing time.
    March 10, 2017   doi: 10.1111/tgis.12267   open full text
  • Partial polygon pruning of hydrographic features in automated generalization.
    Alexander K. Stum, Barbara P. Buttenfield, Lawrence V. Stanislawski.
    Transactions in GIS. March 08, 2017
    This article demonstrates a working method to automatically detect and prune portions of waterbody polygons to support creation of a multi‐scale hydrographic database. Water features are sensitive to scale change, therefore multiple representations are required to maintain visual and geographic logic at smaller scales. Partial pruning of polygonal features – such as long, sinuous reservoir arms, stream channels too narrow at the target scale, and islands that begin to coalesce – entails concurrent management of the length and width of polygonal features as well as integrating pruned polygons with other generalized point and linear hydrographic features to maintain stream network connectivity. The implementation follows data representation standards developed by the US Geological Survey (USGS) for the National Hydrography Dataset (NHD). Portions of polygonal rivers, streams, and canals are automatically characterized for width, length, and connectivity. This article describes an algorithm for automatic detection and subsequent processing, and shows results for a sample of NHD subbasins in different landscape conditions in the US.
    March 08, 2017   doi: 10.1111/tgis.12270   open full text
  • Spheroidal equal angular DEMs: The specificity of morphometric treatment.
    Igor V. Florinsky.
    Transactions in GIS. February 15, 2017
    Digital elevation models (DEMs) are commonly constructed using two main types of regular grids: plane square grids and spheroidal equal angular grids. Methods and algorithms intended for plane square‐gridded DEMs should not be directly applied to spheroidal equal angular DEMs. This is because these grids have fundamentally different geometry. However, some researchers continue to apply square‐grid algorithms to spheroidal equal angular DEMs. It seems appropriate to consider once again the specifity of morphometric treatment of spheroidal equal angular DEMs. This article, first, demonstrates possibilities of direct calculation of local, nonlocal, and combined morphometric variables from spheroidal equal angular DEMs exemplified by slope gradient, catchment area, and topographic index. Second, the article shows computational errors when algorithms for plane square‐gridded DEMs are unreasonably applied to spheroidal equal angular DEMs. The study is exemplified by two DEMs. A medium‐resolution DEM of a relatively small, high‐mountainous area (Mount Elbrus) was extracted from the SRTM1 DEM. A low‐resolution DEM of a vast region with the diverse topography (the central and western regions of Kenya) was extracted from the SRTM30_PLUS DEM. The results show that application of square‐grid methods to spheroidal equal angular DEMs leads to substantial computational errors in models of morphometric variables.
    February 15, 2017   doi: 10.1111/tgis.12269   open full text
  • Context inference and prediction modeling in ubiquitous health GIS.
    Neda Kaffash‐Charandabi, Ali‐Asghar Alesheikh.
    Transactions in GIS. February 08, 2017
    The ever‐increasing population in cities intensifies environmental pollution that increases the number of asthmatic patients. Other factors that may influence the prevalence of asthma are atmospheric parameters, physiographic elements and personal characteristics. These parameters can be incorporated into a model to monitor and predict the health conditions of asthmatic patients in various contexts. Such a model is the base for any asthma early warning system. This article introduces a novel ubiquitous health system to monitor asthmatic patients. Ubiquitous systems can be effective in monitoring asthmatic patients through the use of intelligent frameworks. They can provide powerful reasoning and prediction engines for analyzing various situations. Our proposed model encapsulates several tools for preprocessing, reasoning and prediction of asthma conditions. In the preprocessing phase, outliers in the atmospheric datasets were detected and missing sensor data were estimated using a Kalman filter, while in the reasoning phase, the required information was inferred from the raw data using some rule‐based inference techniques. The asthmatic conditions of patients were predicted accurately by a Graph‐Based Support Vector Machine in a Context Space (GBSVMCS) which functions anywhere, anytime and with any status. GBSVMCS is an improved version of the common Support Vector Machine algorithm with the addition of unlabeled data and graph‐based rules in a context space. Based on the stored value for a patient's condition and his/her location/time, asthmatic patients can be monitored and appropriate alerts will be given. Our proposed model was assessed in Region 3 of Tehran, Iran for monitoring three different types of asthma: allergic, occupational and seasonal asthma. The input data to our system included air pollution data, the patients’ personal information, patients’ locations, weather data and geographical information for 270 different situations. Our results showed that 90% of the system's predictions were correct. The proposed model also improved the estimation accuracy by 15% in comparison to conventional methods.
    February 08, 2017   doi: 10.1111/tgis.12263   open full text
  • Geometric quality assessment of trajectory‐generated VGI road networks based on the symmetric arc similarity.
    Haiyang Lyu, Yehua Sheng, Ningning Guo, Baoqun Huang, Siyang Zhang.
    Transactions in GIS. January 13, 2017
    As large amounts of trajectories from a wide variety of Volunteered Geographic Information (referred to as VGI) contributors pour into the spatial database, the geometric qualities of the VGI road networks generated from these trajectories are different from the ground truth road dataset and so need to be differently assessed. To address this issue, an assessment approach based on symmetric arc similarity is proposed, and the geometric quality of a VGI road network is assessed by its conformity with the corresponding ground truth road network, the results being visualized as hierarchical thematic maps. To compute the conformity, the geometric similarity between the VGI road arc and the corresponding ground truth road arc, which is selected by the adaptive searching distance, is measured based on the symmetric arc similarity method; the geometric quality is assessed based on an assessment matrix. Also, the symmetric arc similarity method is independent of directions and with a feature of shift‐independence, which is applicable to assess the geometric qualities of different VGI road networks and makes the assessment result consistent with the actual situation of the real world. The robustness and scalability of the approach are examined using VGI road networks from different sources.
    January 13, 2017   doi: 10.1111/tgis.12256   open full text
  • A site selection method of DNS using the particle swarm optimization algorithm.
    Yilan Liao, Wenwen Chen, Kaichao Wu, Dongyue Li, Xin Liu, Guanggang Geng, Zheng Su, Zheng Zheng.
    Transactions in GIS. December 26, 2016
    The Domain Name System (DNS) is an essential component of the functionality of the Internet. With the growing number of domain names and Internet users, the growing rate and number of visit quantity and analytic capacity of DNS are also proportional to the Internet users' size. This study (based on the analysis of access popularity and the distribution of massive DNS log data) aims to optimize the configuration of the DNS sites, which has become an important problem. The ArcGIS software is used to show the temporal and spatial distributions of visit source of DNS logs. This study also analyzes the influence of different sites and the dependence on DNS service in different regions of the world. This information is important to further decision‐making on new DNS site selection. This article proposes new DNS site selection solutions, using particle swarm and multi‐objective particle swarm optimization algorithms for one new site and multiple sites, respectively. The results from particle swarm optimization, genetic, and simulated annealing algorithms were compared and experimental results confirmed the correctness and effectiveness of the proposed methods. The proposed methods could also be extended to solve other layout related issues, such as onsite facility layout and road network optimization.
    December 26, 2016   doi: 10.1111/tgis.12244   open full text
  • Geographically weighted regression‐based determinants of malaria incidences in northern China.
    Yong Ge, Yongze Song, Jinfeng Wang, Wei Liu, Zhoupeng Ren, Junhuan Peng, Binbin Lu.
    Transactions in GIS. December 22, 2016
    Geographically weighted regression (GWR) is an important local method to explore spatial non‐stationarity in data relationships. It has been repeatedly used to examine spatially varying relationships between epidemic diseases and predictors. Malaria, a serious parasitic disease around the world, shows spatial clustering in areas at risk. In this article, we used GWR to explore the local determinants of malaria incidences over a 7‐year period in northern China, a typical mid‐latitude, high‐risk malaria area. Normalized difference vegetation index (NDVI), land surface temperature (LST), temperature difference, elevation, water density index (WDI) and gross domestic product (GDP) were selected as predictors. Results showed that both positively and negatively local effects on malaria incidences appeared for all predictors except for WDI and GDP. The GWR model calibrations successfully depicted spatial variations in the effect sizes and levels of parameters, and also showed substantially improvements in terms of goodness of fits in contrast to the corresponding non‐spatial ordinary least squares (OLS) model fits. For example, the diagnostic information of the OLS fit for the 7‐year average case is R2 = 0.243 and AICc = 837.99, while significant improvement has been made by the GWR calibration with R2 = 0.800 and AICc = 618.54.
    December 22, 2016   doi: 10.1111/tgis.12259   open full text
  • The interrelated use of geological information and other types of geoinformation in local governments.
    Elisabeth Häggquist.
    Transactions in GIS. December 16, 2016
    There is a growing interest in the use of geoinformation in government decision‐making. Studies on the usability of geological information, which is one type of geoinformation, have however been scarce in the literature. A system built for an efficient organization may, therefore, not be catering to the needs of the individual user and understanding the perceived barriers to using geological information should be an important goal of geodata implementation. The objectives of this article are to: (1) investigate whether the analyses of user patterns are improved by considering an interrelated estimation with two types of geoinformation, and (2) explore whether there are gender differences in how peer advice affects the use of geoinformation. The data were collected in 2014 through a web survey, and the sample consisted of 390 women and 287 men working in Swedish municipalities. The results indicates a more accurate prediction pattern when a secondary geoinformation decision was included, thus suggesting that different types of geoinformation should be jointly analyzed. The officials tend to use both types of geoinformation, alluding to a demand for combined geoinformation products among the target population. Finally, there is evidence of women's decision to use geoinformation being affected by peer advice.
    December 16, 2016   doi: 10.1111/tgis.12258   open full text
  • Completeness and classification correctness of features on topographic maps: An analysis of the estonian basic map.
    Kiira Mõisja, Tõnu Oja, Evelyn Uuemaa, Jordan T. Hastings.
    Transactions in GIS. December 12, 2016
    In an increasingly GIS‐literate world, the availability of quality topographic maps and map databases is critical for the numerous users of spatial data. Particularly governmental agencies, first responders, and utility and transportation services, rely on the completeness and classification correctness of these maps. Estonia has systematically updated its topographic Basic Map in digital form over the past 15 years. An analysis of the Estonian production process in the period 2003‐2006 provides a useful case study of both error types and error frequencies encountered in topographic mapping. Errors of completeness and classification correctness of topographic features are analyzed at two levels of specificity: in general, across all map sheets, and in detail according to the field‐workers who performed the mapping. The structure of errors at the two levels was different by geometry and error types; however, both systematic and individual errors were evident. The systematic errors indicated a need for revision and improvement of the data capture specifications, which was accomplished. The individual errors were addressed by additional training for the field‐workers involved.
    December 12, 2016   doi: 10.1111/tgis.12257   open full text
  • An effective spherical panoramic LoD model for a mobile street view service.
    Xianxiong Liu, Qingwu Hu, Mingyao Ai, Pengcheng Zhao, Dengbo Yu.
    Transactions in GIS. December 06, 2016
    Street view (panoramic view) services have begun to shift from PC platforms to mobile smart devices. Considering the capabilities of smart terminal devices, a 360° spherical level of detail (LoD) model for mobile street view services that renders panoramic images on the inner surface of a sphere via LoD is proposed in this article. Panoramic images are segmented into tiles and organized in a pyramid tile structure for LoD rendering to improve the rendering efficiency of the proposed model. A projection model between panoramic images and the spherical surface is presented to map the panoramic tiles on the spherical graticule. A street view‐rendering algorithm of panoramic images is proposed with the rendering function of OpenGL for Embedded Systems (OpenGL ES). A street view service app running on Android, based on the proposed approach, is implemented to assess two aspects of the panoramic view model, namely visualization effect and efficiency. Experiment results reveal that the 360° spherical LoD model of the panoramic image can display 3D street view scenes better than the cubic panoramic view model. The proposed model also has an excellent 3D visualization effect and high‐efficiency rendering ability for mobile street view services. Therefore, it is applicable in large‐scale mobile street view services both online and offline and in augmented reality navigation.
    December 06, 2016   doi: 10.1111/tgis.12247   open full text
  • Multi‐scale approach to mining significant spatial co‐location patterns.
    Min Deng, Zhanjun He, Qiliang Liu, Jiannan Cai, Jianbo Tang.
    Transactions in GIS. December 06, 2016
    Spatial co‐location pattern mining aims to discover a collection of Boolean spatial features, which are frequently located in close geographic proximity to each other. Existing methods for identifying spatial co‐location patterns usually require users to specify two thresholds, i.e. the prevalence threshold for measuring the prevalence of candidate co‐location patterns and distance threshold to search the spatial co‐location patterns. However, these two thresholds are difficult to determine in practice, and improper thresholds may lead to the misidentification of useful patterns and the incorrect reporting of meaningless patterns. The multi‐scale approach proposed in this study overcomes this limitation. Initially, the prevalence of candidate co‐location patterns is measured statistically by using a significance test, and a non‐parametric model is developed to construct the null distribution of features with the consideration of spatial auto‐correlation. Next, the spatial co‐location patterns are explored at multi‐scales instead of single scale (or distance threshold) discovery. The validity of the co‐location patterns is evaluated based on the concept of lifetime. Experiments on both synthetic and ecological datasets show that spatial co‐location patterns are discovered correctly and completely by using the proposed method; on the other hand, the subjectivity in discovery of spatial co‐location patterns is reduced significantly.
    December 06, 2016   doi: 10.1111/tgis.12261   open full text
  • An adaptive dual clustering algorithm based on hierarchical structure: A case study of settlement zoning.
    Yaolin Liu, Xiaomi Wang, Dianfeng Liu, Leilei Liu.
    Transactions in GIS. November 21, 2016
    Traditional dual clustering algorithms cannot adaptively perform clustering well without sufficient prior knowledge of the dataset. This article aims at accommodating both spatial and non‐spatial attributes in detecting clusters without the need to set parameters by default or prior knowledge. A novel adaptive dual clustering algorithm (ADC+) is proposed to obtain satisfactory clustering results considering the spatial proximity and attribute similarity with the presence of noise and barriers. In this algorithm, Delaunay triangulation is utilized to adaptively obtain spatial proximity and spatial homogenous patterns based on particle swarm optimization (PSO). Then, a hierarchical clustering method is employed to obtain clusters with similar attributes. The hierarchical clustering method adopts a discriminating coefficient to adaptively control the depth of the hierarchical architecture. The clustering results are further refined using an optimization approach. The advantages and practicability of the ADC+ algorithm are illustrated by experiments on both simulated datasets and real‐world applications. It is found that the proposed ADC+ algorithm can adaptively and accurately detect clusters with arbitrary shapes, similar attributes and densities under the consideration of barriers.
    November 21, 2016   doi: 10.1111/tgis.12246   open full text
  • Toward a working taxonomy of geodesign practice.
    David Tulloch.
    Transactions in GIS. November 06, 2016
    As an emerging area of study, geodesign discussions and publications have used practice as a vital source of inspiration and evidence of the early successes of the field. A closer examination of geodesign projects reveals some similarities and differences within the practice currently discussed as geodesign. Using 28 examples of geodesign projects, this paper identifies classes of examples that are similar. Based on the practical evidence represented in the examples, a 3‐level classification system is proposed for providing a basic taxonomy for geodesign projects. This taxonomic system characterizes the classes based on: (1) whether the examples ceded some design control to the computer; (2) whether public participation is incorporated into the design process; and (3) whether it employs complex substantive models. This taxonomy offers a means for understanding and describing the diversity of geodesign while also raising new questions about the boundaries and structure of the field.
    November 06, 2016   doi: 10.1111/tgis.12245   open full text
  • Reference data enhancement for geographic information retrieval using linked data.
    Tiago H. V. M. Moura, Clodoveu A. Davis, Frederico T. Fonseca.
    Transactions in GIS. November 02, 2016
    Gazetteers are instrumental in recognizing place names in documents such as Web pages, news, and social media messages. However, creating and maintaining gazetteers is still a complex task. Even though some online gazetteers provide rich sets of geographic names in planetary scale (e.g. GeoNames), other sources must be used to recognize references to urban locations, such as street names, neighborhood names or landmarks. We propose integrating Linked Data sources to create a gazetteer that combines a broad coverage of places with urban detail, including content on geographic and semantic relationships involving places, their multiple names and related non‐geographic entities. Our final goal is to expand the possibilities for recognizing, disambiguating and filtering references to places in texts for geographic information retrieval (GIR) and related applications. The resulting ontological gazetteer, named LoG (Linked OntoGazetteer), is accessible through Web services by applications and research initiatives on GIR, text processing, named entity recognition and others. The gazetteer currently contains over 13 million places, 140 million attributes and relationships, and 4.5 million non‐geographic entities. Data sources include GeoNames, Freebase, DBPedia and LinkedGeoData, which is based on OpenStreetMap data. An analysis on how these datasets overlap and complement one another is also presented.
    November 02, 2016   doi: 10.1111/tgis.12238   open full text
  • An innovative GPS trajectory data based model for geographic recommendation service.
    Zhiqiang Zou, Zhe Yu, Kai Cao.
    Transactions in GIS. November 02, 2016
    Geographic services based on GPS trajectory data, such as location prediction and recommender services, have received increasing attention because of their potential social and commercial benefits. In this study, a Geographic Service Recommender Model (GSRM) is proposed, which loosely comprises three essential steps. Firstly, location sequences are obtained through a clustering operation on GPS locations. To improve efficiency, a programming model with a distributed algorithm is employed to accelerate the clustering. Secondly, in order to mine spatial and temporal information from the cluster trajectory, an algorithm (MiningMP) is designed. Last but not least, the next possible location to which the user will travel is predicted. An integrated framework of GSRM could then be constructed and provide the appropriate geographic recommendation service by considering location sequences as well as other related semantic information. Experiments were conducted based on real GPS trajectories from Microsoft Research Asia (182 users within a period of five years). The experimental results clearly demonstrate that our proposed GSRM model is effective and efficient at predicting locations and can provide users with personalized smart recommendation services in the following possible position with excellent performance in scalability, adaptability, and quality of service.
    November 02, 2016   doi: 10.1111/tgis.12248   open full text
  • Landmark‐based summarized messages for flood warning.
    Ya‐Hui Chang, Yu‐Te Liu, Yi‐Yuan Tan.
    Transactions in GIS. October 20, 2016
    In order to evacuate residents in time, flood warning systems must have rapid data processing algorithms to translate detailed numerical data into simple warnings and navigation aids. Although it is common to display warning messages by directly drawing red circles on a map embedded in a Web page to indicate the regions about to be inundated, such an approach has some drawbacks. We propose an alternative way by summarizing the warning messages based on landmarks, so that the messages can be short and convey even more information. We have designed two approaches to output such messages. They are the nearest landmark approach and the threshold approach, which differ in the way of determining which landmarks will be influenced by a certain flooded region. These two methods are implemented and we compare their performance through real and synthetic datasets. Experimental results show that the threshold approach usually takes less execution time than the nearest landmark approach. Its severity ranking of landmarks is also better suited to human behaviour.
    October 20, 2016   doi: 10.1111/tgis.12241   open full text
  • An evaluation of sampling and full enumeration strategies for Fisher Jenks classification in big data settings.
    Sergio J. Rey, Philip Stephens, Jason Laura.
    Transactions in GIS. October 04, 2016
    Large data contexts present a number of challenges to optimal choropleth map classifiers. Application of optimal classifiers to a sample of the attribute space is one proposed solution. The properties of alternative sampling‐based classification methods are examined through a series of Monte Carlo simulations. The impacts of spatial autocorrelation, number of desired classes, and form of sampling are shown to have significant impacts on the accuracy of map classifications. Tradeoffs between improved speed of the sampling approaches and loss of accuracy are also considered. The results suggest the possibility of guiding the choice of classification scheme as a function of the properties of large data sets.
    October 04, 2016   doi: 10.1111/tgis.12236   open full text
  • Collaborative personalized multi‐criteria wayfinding for wheelchair users in outdoors.
    Mahdi Hashemi, Hassan A. Karimi.
    Transactions in GIS. September 26, 2016
    While finding the optimal route for users with physical disabilities and personalizing routes for each user, on the one hand, and collaborative wayfinding, on the other hand, have been addressed in the pedestrian navigation systems literature, there has not been much research on combining the two activities. The problem associated with wayfinding approaches solely based on information about network segments and personal preferences is that the information about segments in the database may not, correctly and/or adequately address user preferences. The problem associated with wayfinding approaches solely based on the ratings given to routes by wheelchair users is the lack of rates (or scores) for all possible routes between all possible origin‐destination pairs in the network. This article discusses an approach to combine these two approaches for wayfinding to augment each other's shortcomings. To evaluate the personalized wayfinding approach, we utilize a route index, called a comparison index. The results show that with a P‐value of 9%, the routes obtained from our approach are more accessible than the routes obtained from another approach developed in another study. To evaluate the collaborative wayfinding approach, a Monte Carlo simulation was conducted which reflects the updates in routes as users' feedbacks become available.
    September 26, 2016   doi: 10.1111/tgis.12230   open full text
  • Addressing location uncertainties in GPS‐based activity monitoring: A methodological framework.
    Neng Wan, Ge Lin Kan, Gaines Wilson.
    Transactions in GIS. September 19, 2016
    Location uncertainty has been a major barrier in information mining from location data. Although the development of electronic and telecommunication equipment has led to an increased amount and refined resolution of data about individuals’ spatio‐temporal trajectories, the potential of such data, especially in the context of environmental health studies, has not been fully realized due to the lack of methodology that addresses location uncertainties. This article describes a methodological framework for deriving information about people's continuous activities from individual‐collected Global Positioning System (GPS) data, which is vital for a variety of environmental health studies. This framework is composed of two major methods that address critical issues at different stages of GPS data processing: (1) a fuzzy classification method for distinguishing activity patterns; and (2) a scale‐adaptive method for refining activity locations and outdoor/indoor environments. Evaluation of this framework based on smartphone‐collected GPS data indicates that it is robust to location errors and is able to generate useful information about individuals’ life trajectories.
    September 19, 2016   doi: 10.1111/tgis.12231   open full text
  • Spatially filtered ridge regression (SFRR): A regression framework to understanding impacts of land cover patterns on urban climate.
    Chao Fan, Sergio J. Rey, Soe W. Myint.
    Transactions in GIS. September 04, 2016
    Understanding the impacts of land cover pattern on the heat island effect is essential for sustainable urban development. Conventional model fitting methods have restricted ability to produce accurate estimates of the land cover‐temperature association due to the lack of procedures to address two important issues: spatial dependence in proximal spatial units and high correlations among predictor variables. In this study, we seek to develop an effective framework called spatially filtered ridge regression (SFRR) to estimate the variations in the quantity and distribution of land surface temperature (LST) in response to various land cover patterns. The SFRR effectively integrates spatial autoregressive models and ridge regression, and it achieves reliable parameter estimates with substantially reduced mean square errors. We show this by comparing the performance of the SFRR to other widely adopted models using Monte Carlo simulation followed by an empirical study over central Phoenix. Results highlight the great potential of the SFRR in producing accurate statistical estimates, providing a positive step toward informed and unbiased decision‐making across a wide variety of disciplines. (Code and data to reproduce the results in the case study are available at:
    September 04, 2016   doi: 10.1111/tgis.12240   open full text
  • An intersection‐based trajectory‐region movement study.
    Longgang Xiang, Tao Wu, Dick Ettema.
    Transactions in GIS. September 04, 2016
    In order to better understand the movement of an object with respect to a region, we propose a formal model of the evolving spatial relationships that transition between local topologies with respect to a trajectory and a region as well as develop a querying mechanism to analyze movement patterns. We summarize 12 types of local topologies built on trajectory‐region intersections, and derive their transition graph; then we capture and model evolving local topologies with two types of trajectory‐region strings, a movement string and a stop‐move string. The stop‐move string encodes the stop information further during a trajectory than the movement string. Such a string‐format expression of trajectory‐region movement, although conceptually simple, carries unprecedented information for effectively interpreting how trajectories move with respect to regions. We also design the corresponding Finite State Automations for a movement string as well as a stop‐move string, which are used not only to recognize the language of trajectory‐region strings, but also to deal effectively with trajectory‐region pattern queries. When annotated with the time information of stops and intersections, a trajectory‐region movement snapshot and its evolution during a time interval can be inferred, and even the relationships among trajectories with respect to the same region can be explored.
    September 04, 2016   doi: 10.1111/tgis.12220   open full text
  • SCOPED‐W: SCalable Online Platform for extracting Environmental Data and Water‐related model outputs.
    Yaniss Guigoz, Pierre Lacroix, Elham Rouholahnejad, Nicolas Ray, Grégory Giuliani.
    Transactions in GIS. August 28, 2016
    This article presents SCOPED, an innovative approach for extracting environmental data using OGC services. In the field of water resource management, SCOPED‐W (‘W’ for ‘Water’) is a method that was developed in the framework of EU/FP7 IASON and EOPOWER projects. This platform supports the collection of data required to build a Soil and Water Assessment Tool (SWAT) model and the uptake, spatialization and dissemination of raw data generated from the outputs of different SWAT models for the Black Sea region. Scientists are documenting the data served by the platform in ISO standardized metadata to support informed use. SCOPED‐W primarily targets the community of SWAT users in the Black Sea region but it can easily be replicated in other geographical areas. Additionally, the SCOPED approach is based on data interoperability that makes it fully compatible with other domains of application as demonstrated here with three original use cases. The article also highlights the benefits of the approach for the GEO community and discusses future improvements for supporting integration with other platforms such as UNEP Live.
    August 28, 2016   doi: 10.1111/tgis.12227   open full text
  • Using Spatial Analysis to Understand the Spatial Heterogeneity of Disability Employment in China.
    Yilan Liao, Jinfeng Wang, Wei Du, Bingbo Gao, Xin Liu, Gong Chen, Xinming Song, Xiaoying Zheng.
    Transactions in GIS. August 19, 2016
    During the formulation of employment disability policy, policymakers are often interested in regional variations of disability employment. Decision‐makers are required to distinguish between various geographical factors. However, few previous studies take spatial heterogeneity into account and most of them conducted only a qualitative analysis. Geographical detectors based on spatial variation analyses of identified factors were applied in the study to establish connections between regional features and the disability employment rate, and to identify the city groups with significantly higher and lower percentage rates of disability employment. It is the first application of spatial statistics in studying the employment problem of the disabled. The findings can help the government formulate reasonable adjustments to both job opportunities for, and work roles of, disabled people.
    August 19, 2016   doi: 10.1111/tgis.12217   open full text
  • A high accuracy surface modeling method based on GPU accelerated multi‐grid method.
    Changqing Yan, Jimin Liu, Gang Zhao, Chuanfa Chen, Tianxiang Yue.
    Transactions in GIS. August 15, 2016
    A high accuracy surface modeling method (HASM) has been developed to provide a solution to many surface modeling problems such as DEM construction, surface estimation and spatial prediction. Although HASM is able to model surfaces with a higher accuracy, its low computing speed limits its popularity in constructing large scale surfaces. Hence, the research described in this article aims to improve the computing efficiency of HASM with a graphic processor unit (GPU) accelerated multi‐grid method (HASM‐GMG). HASM‐GMG was tested with two types of surfaces: a Gauss synthetic surface and a real‐world example. Results indicate that HASM‐GMG can gain significant speedups compared with CPU‐based HASM without acceleration on GPU. Moreover, both the accuracy and speed of HASM‐GMG are superior to the classical interpolation methods including Kriging, Spline and IDW.
    August 15, 2016   doi: 10.1111/tgis.12224   open full text
  • An open source GIS‐based Planning Support System: Application to the land use plan of La Troncal, Ecuador.
    Inés Santé, Natalia Pacurucu, Marcos Boullón, Andrés Manuel García, David Miranda.
    Transactions in GIS. August 15, 2016
    Planning Support Systems (PSS) comprise a wide variety of geo‐technological tools related to GIS and spatial modeling aimed at addressing land planning processes. This article describes the OpenRules system, a PSS based on a previous system called RULES. Among OpenRules new features are its architecture, based exclusively on free and open source software, and its applicability to all land use types, including rural and urban uses. In addition, OpenRules incorporates an unlimited number of land evaluation factors and a new objective in land use spatial allocation. OpenRules has been programmed in Java and implemented as a module of the free GIS software gvSIG, with full integration between the GIS and the decision support tools. Decision support tools include multicriteria evaluation, multiobjective linear programming and heuristic techniques, which support three basic stages of land use planning processes, namely land suitability evaluation, land use area optimization and land use spatial allocation. The application of OpenRules to the region of La Troncal, Ecuador, demonstrates its capability to generate alternative and coherent solutions through a scientific and justified procedure at low cost in terms of time and resources.
    August 15, 2016   doi: 10.1111/tgis.12223   open full text
  • Establishing robustness of a spatial dataset in a tolerance‐based vector model.
    Alberto Belussi, Sara Migliorini, Mauro Negri, Giuseppe Pelagatti.
    Transactions in GIS. August 01, 2016
    Spatial data are usually described through a vector model in which geometries are represented by a set of coordinates embedded into an Euclidean space. The use of a finite representation, instead of the real numbers theoretically required, causes many robustness problems which are well known in the literature. Such problems are made even worse in a distributed context, where data is exchanged between different systems and several perturbations can be introduced in the data representation. In order to discuss the robustness of a spatial dataset, two implementation models have to be distinguished: the identity and the tolerance model. The robustness of a dataset in the identity model has been widely discussed in the literature and some algorithms of the Snap Rounding (SR) family can be successfully applied in such contexts. Conversely, this problem has been less explored in the tolerance model. The aim of this article is to propose an algorithm inspired by those of the SR family for establishing or restoring the robustness of a vector dataset in the tolerance model. The main ideas are to introduce an additional operation which spreads instead of snapping geometries, in order to preserve the original relation between them, and to use a tolerance region for such an operation instead of a single snapping location. Finally, some experiments on real‐world datasets are presented, confirming how the proposed algorithm can establish the robustness of a dataset.
    August 01, 2016   doi: 10.1111/tgis.12221   open full text
  • Total 3D‐viewshed Map: Quantifying the Visible Volume in Digital Elevation Models.
    Antonio Rodriguez Cervilla, Siham Tabik, Jesús Vías, Matías Mérida, Luis F. Romero.
    Transactions in GIS. July 01, 2016
    The 3D perception of the human eye is more impressive in irregular land surfaces than in flat land surfaces. The quantification of this perception would be very useful in many applications. This article presents the first approach to determining the visible volume, which we call the 3D‐viewshed, in each and all the points of a DEM (Digital Elevation Model). Most previous visibility algorithms in GIS (Geographic Information Systems) are based on the concept of a 2D‐viewshed, which determines the number of points that can be seen from an observer in a DEM. Extending such a 2D‐viewshed to 3D space, then to all the DEM‐points, is too expensive computationally since the viewshed computation per se is costly. In this work, we propose the first approach to compute a new visibility metric that quantifies the visible volume from every point of a DEM. In particular, we developed an efficient algorithm with a high data and calculation re‐utilization. This article presents the first total‐3D‐viewshed maps together with validation results and comparative analysis. Using our highly scalable parallel algorithm to compute the total‐3D‐viewshed of a DEM with 4 million points on a Xeon Processor E5‐2698 takes only 1.3 minutes.
    July 01, 2016   doi: 10.1111/tgis.12216   open full text
  • The Minimum Step Linkage Algorithm and Cumulative Cost Model for Time‐Dependent Shortest Paths.
    Vini Indriasari, Denis Dean.
    Transactions in GIS. July 01, 2016
    Real‐word road networks are typically time‐dependent, but research on time‐dependent shortest paths (TDSPs) is not as rich as that on static shortest paths (SSPs). For large networks, some speed‐up techniques are usually applied to compute SSPs. Unfortunately, many of these techniques are impractical for TDSPs, especially the techniques requiring a precomputation because the number of time instances may be incredibly large or even infinite. Therefore, this study introduced a new TDSP technique that is able to overcome the issue of infinite time instances by utilizing network geometry alone for the pre‐computation, namely the Minimum Step Linkage (MSL) algorithm. It works with a data model called Cumulative Cost Model (CCM). The theoretical concepts of the new data model and algorithm are described, and its performances were tested and compared with existing algorithms through a series of simulations.
    July 01, 2016   doi: 10.1111/tgis.12215   open full text
  • Improving Large Area Population Mapping Using Geotweet Densities.
    Nirav N. Patel, Forrest R. Stevens, Zhuojie Huang, Andrea E. Gaughan, Iqbal Elyazar, Andrew J. Tatem.
    Transactions in GIS. June 30, 2016
    Many different methods are used to disaggregate census data and predict population densities to construct finer scale, gridded population data sets. These methods often involve a range of high resolution geospatial covariate datasets on aspects such as urban areas, infrastructure, land cover and topography; such covariates, however, are not directly indicative of the presence of people. Here we tested the potential of geo‐located tweets from the social media application, Twitter, as a covariate in the production of population maps. The density of geo‐located tweets in 1x1 km grid cells over a 2‐month period across Indonesia, a country with one of the highest Twitter usage rates in the world, was input as a covariate into a previously published random forests‐based census disaggregation method. Comparison of internal measures of accuracy and external assessments between models built with and without the geotweets showed that increases in population mapping accuracy could be obtained using the geotweet densities as a covariate layer. The work highlights the potential for such social media‐derived data in improving our understanding of population distributions and offers promise for more dynamic mapping with such data being continually produced and freely available.
    June 30, 2016   doi: 10.1111/tgis.12214   open full text
  • A New Combined Assessment of Mixed Uncertainty in Spatial Models: Conceptualization and Implementation.
    J. Fernando Rios, Chris S. Renschler.
    Transactions in GIS. June 30, 2016
    Uncertainty quantification is not often performed in spatial modeling applications, especially when there is a mixture of probabilistic and non‐probabilistic uncertainties. Furthermore, the effect of positional uncertainty is often not assessed, despite its relevance to geographical applications. Although there has been much work in investigating the aforementioned types of uncertainty in isolation, combined approaches have not been much researched. This has resulted in a lack of tools for conducting mixed uncertainty analyses that include positional uncertainty. This research addresses the issue by first presenting a new, flexible, simulation‐oriented conceptualization of positional uncertainty in geographic objects called F‐Objects. F‐Objects accommodates various representations of uncertainty, while remaining conceptually simple. Second, a new Python‐based framework is introduced, termed Wiggly and capable of conducting mixed uncertainty propagation using fuzzy Monte Carlo simulation (FMCS). FMCS combines both traditional Monte Carlo with fuzzy analysis in a so‐called hybrid approach. F‐Objects is implemented within the Wiggly framework, resulting in a tool capable of considering any combination of: (1) probabilistic variables; (2) fuzzy variables; and (3) positional uncertainty of objects (probabilistic/fuzzy). Finally, a realistic GIS‐based groundwater contamination problem demonstrates how F‐Objects and Wiggly can be used to assess the effect of positional uncertainty.
    June 30, 2016   doi: 10.1111/tgis.12219   open full text
  • Modeling spatiotemporal pattern of agriculture‐feasible land in China.
    Weihe Wendy Guan, Kang Wu, Fei Carnes.
    Transactions in GIS. June 28, 2016
    This study applies a spatial fuzzy multi‐criteria evaluation model to determine agricultural feasibility in China based on physical variables (accumulated temperature, sunshine, precipitation, hydrology, elevation and soil properties). The resulting agricultural feasibility index layer is combined with nightlight images (1992‐2013) to determine the spatiotemporal variation of urban encroachment on feasible agriculture land. It reveals the severity of agricultural land losses to urbanization.
    June 28, 2016   doi: 10.1111/tgis.12225   open full text
  • A hybrid approach to modeling territorial control in violent armed conflicts.
    Ran Tao, Daniel Strandow, Michael Findley, Jean‐Claude Thill, James Walsh.
    Transactions in GIS. June 28, 2016
    Territorial control is central to the understanding of violent armed conflicts, yet reliable and valid measures of this concept do not exist. We argue that geospatial analysis provides an important perspective to measure the concept. In particular, measuring territorial control can be seen as an application of calculating service areas around points of control. The modeling challenge is acute for areas with limited road infrastructure, where no complete network is available to perform the analysis, and movements largely occur off road. We present a new geospatial approach that applies network analysis on a hybrid transportation network with both actual road data and hexagon‐fishnet‐based artificial road data representing on‐road and off‐road movements, respectively. Movement speed or restriction can be readily adjusted using various input data. Simulating off‐road movement with hexagon‐fishnet‐based artificial road data has a number of advantages including scalability to small or large study areas and flexibility to allow all‐directional travel. We apply this method to measuring territorial control of armed groups in Sub‐Saharan Africa where inferior transport infrastructure is the norm. Based on the Uppsala Conflict Data Program's (UCDP) Georeferenced Event Data (GED) as well as spatial data on terrain, population locations, and limited transportation networks, we enhance the delineation of the specific areas directly controlled by each warring party during civil wars within a given travel time.
    June 28, 2016   doi: 10.1111/tgis.12228   open full text
  • Spatial discovery and the research library.
    Sara Lafia, Jon Jablonski, Werner Kuhn, Savannah Cooley, F. Antonio Medrano.
    Transactions in GIS. June 28, 2016
    Academic libraries have always supported research across disciplines by integrating access to diverse contents and resources. They now have the opportunity to reinvent their role in facilitating interdisciplinary work by offering researchers new ways of sharing, curating, discovering, and linking research data. Spatial data and metadata support this process because location often integrates disciplinary perspectives, enabling researchers to make their own research data more discoverable, to discover data of other researchers, and to integrate data from multiple sources. The Center for Spatial Studies at the University of California, Santa Barbara (UCSB) and the UCSB Library are undertaking joint research to better enable the discovery of research data and publications. The research addresses the question of how to spatially enable data discovery in a setting that allows for mapping and analysis in a GIS while connecting the data to publications about them. It suggests a framework for an integrated data discovery mechanism and shows how publications may be linked to associated data sets exposed either directly or through metadata on Esri's Open Data platform. The results demonstrate a simple form of linking data to publications through spatially referenced metadata and persistent identifiers. This linking adds value to research products and increases their discoverability across disciplinary boundaries.
    June 28, 2016   doi: 10.1111/tgis.12235   open full text
  • Crowdsensing smart ambient environments and services.
    Blake Regalia, Grant McKenzie, Song Gao, Krzysztof Janowicz.
    Transactions in GIS. June 28, 2016
    Whether it be Smart Cities, Ambient Intelligence, or the Internet of Things, current visions for future urban spaces share a common core, namely the increasing role of distributed sensor networks and the on‐demand integration of their data to power real‐time services and analytics. Some of the greatest hurdles to implementing these visions include security risks, user privacy, scalability, the integration of heterogeneous data, and financial cost. In this work, we propose a crowdsensing mobile‐device platform that empowers citizens to collect and share information about their surrounding environment via embedded sensor technologies. This approach allows a variety of urban areas (e.g., university campuses, shopping malls, city centers, suburbs) to become equipped with a free ad‐hoc sensor network without depending on proprietary instrumentation. We present a framework, namely the GeoTracer application, as a proof‐of‐concept to conduct multiple experiments simulating use‐case scenarios on a university campus. First, we demonstrate that ambient sensors (e.g. temperature, pressure, humidity, magnetism, illuminance, and audio) can help determine a change in environment (e.g. moving from indoors to outdoors, or floor changes inside buildings) more accurately than typical positioning technologies (e.g. global navigation satellite system, Wi‐Fi, etc.). Furthermore, each of these sensors contributes a different amount of data to detecting events. for example, illuminance has the highest information gain when trying to detect changes between indoors and outdoors. Second, we show that through this platform it is possible to detect and differentiate place types on a university campus based on inferences made through ambient sensors. Lastly, we train classifiers to determine the activities that a place can afford at different times (e.g. good for studying or not, basketball courts in use or empty) based on sensor‐driven semantic signatures.
    June 28, 2016   doi: 10.1111/tgis.12233   open full text
  • An intelligent geospatial processing unit for image classification based on geographic vector agents (GVAs).
    Kambiz Borna, Antoni B. Moore, Pascal Sirguey.
    Transactions in GIS. June 28, 2016
    Spatial modeling methods usually use pixels and image objects as fundamental processing units to address real‐world objects, geo‐objects, in image space. To do this, both pixel‐based and object‐based approaches typically employ a linear two‐staged workflow of segmentation and classification. Pixel‐based methods segment a classified image to address geo‐objects in image space. In contrast, object‐based approaches classify a segmented image to identify geo‐objects from raster datasets. These methods lack the ability to simultaneously integrate the geometry and theme of geo‐objects in image space. This article explores Geographical Vector Agents (GVAs) as an automated and intelligent processing unit to directly address real‐world objects in the process of remote sensing image classification. The GVA is a distinct type of geographic automata characterized by elastic geometry, dynamic internal structure, neighborhoods and their respective rules. We test this concept by modeling a set of objects on a subset IKONOS image and LiDAR DSM datasets without the setting parameters (e.g. scale, shape information), usually applied in conventional Geographic Object‐Based Image Analysis (GEOBIA) approaches. The results show that the GVA approach achieves more than 3.5% improvement for correctness, 2% improvement for quality, although no significant improvement for completeness to GEOBIA, thus demonstrating the competitive performance of GVAs classification.
    June 28, 2016   doi: 10.1111/tgis.12226   open full text
  • Map algebra based analysis for directed flow networks.
    Jiangfeng She, Xingong Li.
    Transactions in GIS. June 28, 2016
    Based on the concept of map algebra, this research developed a network neighborhood analysis framework for directed flow networks. The analysis framework has two components: the first component defines how neighborhoods are delineated on networks and the second component calculates various statistics within the neighborhoods. The power and value of the analysis framework lie in its capability to delineate versatile network neighborhoods and its flexibility in calculating various statistics within the neighborhoods. It extends the raster map algebra to networks and provides a consistent analysis framework for the raster, vector, and network data models. Using a small section of the National Hydrography Dataset (NHD) networks, a prototype Web application is implemented to experiment and demonstrate the concept and uses of the analysis framework.
    June 28, 2016   doi: 10.1111/tgis.12234   open full text
  • Spatial signatures for geographic feature types: examining gazetteer ontologies using spatial statistics.
    Rui Zhu, Yingjie Hu, Krzysztof Janowicz, Grant McKenzie.
    Transactions in GIS. June 28, 2016
    Digital gazetteers play a key role in modern information systems and infrastructures. They facilitate (spatial) search, deliver contextual information to recommended systems, enrich textual information with geographical references, and provide stable identifiers to interlink actors, events, and objects by the places they interact with. Hence, it is unsurprising that gazetteers, such as GeoNames, are among the most densely interlinked hubs on the Web of Linked Data. A wide variety of digital gazetteers have been developed over the years to serve different communities and needs. These gazetteers differ in their overall coverage, underlying data sources, provided functionality, and geographic feature type ontologies. Consequently, place types that share a common name may differ substantially between gazetteers, whereas types labeled differently may, in fact, specify the same or similar places. This makes data integration and federated queries challenging, if not impossible. To further complicate the situation, most popular and widely adopted geo‐ontologies are lightweight and thus under‐specific to a degree where their alignment and matching become nothing more than educated guesses. The most promising approach to addressing this problem, and thereby enabling the meaningful integration of gazetteer data across feature types, seems to be a combination of top‐down knowledge representation with bottom‐up data‐driven techniques such as feature engineering and machine learning. In this work, we propose to derive indicative spatial signatures for geographic feature types by using spatial statistics. We discuss how to create such signatures by feature engineering and demonstrate how the signatures can be applied to better understand the differences and commonalities of three major gazetteers, namely DBpedia Places, GeoNames, and TGN.
    June 28, 2016   doi: 10.1111/tgis.12232   open full text
  • A Spatial Anomaly Points and Regions Detection Method Using Multi‐Constrained Graphs and Local Density.
    Yan Shi, Min Deng, Xuexi Yang, Qiliang Liu.
    Transactions in GIS. June 27, 2016
    Spatial anomalies may be single points or small regions whose non‐spatial attribute values are significantly inconsistent with those of their spatial neighborhoods. In this article, a Spatial Anomaly Points and Regions Detection method using multi‐constrained graphs and local density (SAPRD for short) is proposed. The SAPRD algorithm first models spatial proximity relationships between spatial entities by constructing a Delaunay triangulation, the edges of which provide certain statistical characteristics. By considering the difference in non‐spatial attributes of adjacent spatial entities, two levels of non‐spatial attribute distance constraints are imposed to improve the proximity graph. This produces a series of sub‐graphs, and those with very few entities are identified as candidate spatial anomalies. Moreover, the spatial anomaly degree of each entity is calculated based on the local density. A spatial interpolation surface of the spatial anomaly degree is generated using the inverse distance weight, and this is utilized to reveal potential spatial anomalies and reflect their whole areal distribution. Experiments on both simulated and real‐life spatial databases demonstrate the effectiveness and practicability of the SAPRD algorithm.
    June 27, 2016   doi: 10.1111/tgis.12208   open full text
  • Automated Geocoding of Textual Documents: A Survey of Current Approaches.
    Fernando Melo, Bruno Martins.
    Transactions in GIS. June 17, 2016
    This survey article describes previous research addressing text‐based document geocoding, i.e. the task of predicting the geospatial coordinates of latitude and longitude, that best correspond to an entire document, based on its textual contents. We describe (1) early document geocoding systems that use heuristics over place names mentioned in the text (e.g. names of cities and states), (2) probabilistic language modeling approaches, where generative models are built for different regions in the world (usually considering a discretization based on a rectangular grid) from the words occurring in a set of georeferenced training documents, which are then used to predict per‐region probabilities for previously unseen test documents, (3) combinations of different models and heuristics, including clustering procedures, feature selection approaches, and/or language models built from different sources, and (4) recent approaches based on discriminative classification models.
    June 17, 2016   doi: 10.1111/tgis.12212   open full text
  • Rendering 2D Lines on 3D Terrain Model with Optimization in Visual Quality and Running Performance.
    Jiangfeng She, Xin Tan, Xingchen Guo, Junzhong Tan, Jianlong Liu.
    Transactions in GIS. May 27, 2016
    With the gradual shift from 2D maps to a 3D virtual environment, various visual artifacts were generated by overlaying 2D map symbols on 3D terrain models. This work proposes a novel screen‐based method for rendering 2D vector lines with the accuracy of more than one pixel on the screen in real time. First, screen pixels are inversely projected onto a 3D terrain surface, and then onto the 2D vector plane. Next, these pixels are classified into three categories in terms of their intersection situation with the 2D lines. After that, a multiple sampling process is applied to the pixels that intersect with the 2D lines in order to eliminate visual artifacts, such as intermittence and aliasing (in pixel scale). Finally, a suitable point‐in‐polygon judgment is implemented to color each sample point quickly. The algorithm is realized in a heterogeneously parallel model so that the performance is improved and becomes acceptable.
    May 27, 2016   doi: 10.1111/tgis.12202   open full text
  • Transport Capacity Limit of Urban Street Networks.
    Gang Liu, Peichao Gao, Yongshu Li.
    Transactions in GIS. May 26, 2016
    Network transport is an important aspect of geographical information science, transportation, complex networks, etc. Previous studies have shown that the transport capacity of street networks can be enhanced by improving routing algorithms. However, the upper throughput limit of street networks is unknown in detail. This article studies the transport process of networks and finds that any connected network has a maximum throughput depending on the topological and structural properties of the network. Based on this, the maximum throughput of street networks is obtained. Experiments show that when the street network remains unchanged, the maximum throughput of the street network is limited and is dependent on road capacity and average path length, regardless of adopted routing algorithms. Our findings suggest that the throughput of networks can be improved by increasing node capacity or decreasing average path length, but the maximum transport capacity of the network cannot be greater than the ratio of the sum of all the nodes' capacities to the average path length of the network, no matter what routing strategies are adopted. This study is expected to be a starting point for more sophisticated research in network transport, such as evaluating the inherent throughput of an urban street network.
    May 26, 2016   doi: 10.1111/tgis.12218   open full text
  • Evaluating Topological Queries in Linked Data Using DBpedia and GeoNames in Switzerland and Scotland.
    Rolf Grütter, Ross S. Purves, Lukas Wotruba.
    Transactions in GIS. May 20, 2016
    This article explores the practicability and assesses the quality of searches for Wikipedia pages of topologically related administrative divisions in Switzerland and Scotland via Linked Data. To this end, the quality of searches in the English and German versions of DBpedia is compared, as is that of searches in GeoNames and DBpedia using DBpedia's links to GeoNames or a manually created list of links. In addition, the effects of updates to Swiss municipality borders in the English version of DBpedia on standard quality metrics are studied. It turns out that live searches are practicable with acceptable performance, but that the quality of searches in terms of recall and precision is acceptable only if DBpedia is queried via GeoNames and DBpedia's links to GeoNames are replaced by manually created links. Searches for Scottish unitary authority wards perform poorly for all approaches investigated. Recall and precision are strongly influenced by changes in municipality borders, with a relatively long latency suggesting that, at least in some cases, administrative changes propagate slowly into DBpedia. These results have important implications for those seeking to use location as a means to link data.
    May 20, 2016   doi: 10.1111/tgis.12196   open full text
  • Optimal Stopping Location of a High Speed Train using GIS and Multicriteria Decision‐making.
    Roberto Sañudo, Jose Luis Moura, Ruben Cordera, Angel Ibeas.
    Transactions in GIS. May 20, 2016
    This article develops a methodology using a Geographical Information System (GIS) to evaluate the best location to stop a high speed passenger train when faced with an undesired event. The proposed method is based on multicriteria decision‐making where different stretches of line which could be chosen as the stopping point are ranked depending on the characteristics of the line, the surrounding area and its accessibility for equipment. The method was integrated into the GIS to develop an expert support system for decision makers faced with different kinds of undesired events. It has been applied to a case study on the high speed line between Valladolid and Madrid (Spain). The proposed method is new and has not previously been applied to high speed railway networks and could be adapted to other case studies. The speed of the algorithm provides an almost instantaneous reply within seconds of an emergency situation occurring. The method can therefore be part of an overall support system for decision making in undesired rail events.
    May 20, 2016   doi: 10.1111/tgis.12204   open full text
  • A Review of Sampling Effects and Response Bias in Internet Participatory Mapping (PPGIS/PGIS/VGI).
    Greg Brown.
    Transactions in GIS. May 20, 2016
    Global interest in participatory mapping described as public participation GIS (PPGIS), participatory GIS (PGIS), and volunteered geographic information (VGI) continues to grow, but systematic study of spatial data quality and sampling effects is limited. This article provides a review and meta‐analysis of Internet‐based PPGIS studies conducted during the period 2006–2015 (n=26) to answer the following research questions: (1) How does mapping effort, as a proxy measure for spatial data quality, differ by sampling group? (2) Does the purpose and context of PPGIS influence mapping results? (3) What is the potential for mapping bias through sampling design? (4) Given the results, what should be the focus of future PPGIS research? Mapping effort was highest in sampling groups whose livelihoods were closely related to the purpose of the study, there was greater mapping effort in household sampling groups compared to volunteer groups, and participant domicile had strong effects on mapped results through spatial discounting. The use of online Internet panels provides higher response rates but lower spatial data quality. Future research should focus on increasing sampling response rates, assessing social trade‐offs using alternative spatial weighting schemes, and examining the capacity of the public to select land use alternatives as a complement to traditional expert‐driven planning systems.
    May 20, 2016   doi: 10.1111/tgis.12207   open full text
  • Identifying Environmental and Human Factors Associated With Tick Bites using Volunteered Reports and Frequent Pattern Mining.
    Irene Garcia‐Martí, Raul Zurita‐Milla, Arno Swart, Kees C. van den Wijngaard, Arnold J.H. van Vliet, Sita Bennema, Margriet Harms.
    Transactions in GIS. May 13, 2016
    Tick populations and tick‐borne diseases like Lyme borreliosis have been steadily increasing since the mid‐1990s. Realizing the threat that ticks pose to public health, two Dutch citizen science projects have collected tick bite reports since 2006. This unique volunteered geographical dataset, which currently has nearly 35,000 reports, was used to identify environmental and other circumstantial factors associated with tick bites. For this, we first enriched the tick bite reports with temperature, precipitation, vegetation and volunteered data associated with the location of the tick bite. Using this enriched dataset, we then derived a series of features to characterize the environmental and volunteer‐related conditions in which each tick bite occurred. Next, we discretized these features using the Jenks Natural Breaks algorithm and, after that, we mined frequent environmental patterns associated with tick bites using the AprioriClose algorithm. Finally, we checked that these patterns are specifically associated with the tick bites by comparing them with the frequent patterns mined from pseudo‐random locations. The frequent patterns were visualized using heat maps and ring maps and two representative patterns associated with tick bites were projected into geographic space to study their spatio‐temporal distribution. Our results show that factors linked to human activity are more relevant to model tick bites than seasonal accumulations of temperature, vegetation or precipitation. In particular, the number of warm and dry days per season are present in a significant number of patterns and the majority of tick bites are produced within a distance of half a kilometer of a forest, recreational or built‐up area. The study of patterns in the time‐series revealed that there are several persistent patterns consistently occurring each year and the validation process showed that the volunteer tick bites collection is capturing environmental conditions associated with tick bites, suggesting that these reports have a high scientific value. These results support the creation of a Dutch tick bite risk map that, in turn, will open the door to the design of public health interventions to reduce the incidence of Lyme disease.
    May 13, 2016   doi: 10.1111/tgis.12211   open full text
  • A Parallel Scheme for Large‐scale Polygon Rasterization on CUDA‐enabled GPUs.
    Chen Zhou, Zhenjie Chen, Yuzhe Pian, Ningchuan Xiao, Manchun Li.
    Transactions in GIS. May 13, 2016
    This research develops a parallel scheme to adopt multiple graphics processing units (GPUs) to accelerate large‐scale polygon rasterization. Three new parallel strategies are proposed. First, a decomposition strategy considering the calculation complexity of polygons and limited GPU memory is developed to achieve balanced workloads among multiple GPUs. Second, a parallel CPU/GPU scheduling strategy is proposed to conceal the data read/write times. The CPU is engaged with data reads/writes while the GPU rasterizes the polygons in parallel. This strategy can save considerable time spent in reading and writing, further improving the parallel efficiency. Third, a strategy for utilizing the GPU's internal memory and cache is proposed to reduce the time required to access the data. The parallel boundary algebra filling (BAF) algorithm is implemented using the programming models of compute unified device architecture (CUDA), message passing interface (MPI), and open multi‐processing (OpenMP). Experimental results confirm that the implemented parallel algorithm delivers apparent acceleration when a massive dataset is addressed (50.32 GB with approximately 1.3 × 108 polygons), reducing conversion time from 25.43 to 0.69 h, and obtaining a speedup ratio of 36.91. The proposed parallel strategies outperform the conventional method and can be effectively extended to a CPU‐based environment.
    May 13, 2016   doi: 10.1111/tgis.12213   open full text
  • A Method for Matching Crowd‐sourced and Authoritative Geospatial Data.
    Heshan Du, Natasha Alechina, Michael Jackson, Glen Hart.
    Transactions in GIS. May 09, 2016
    A method for matching crowd‐sourced and authoritative geospatial data is presented. A level of tolerance is defined as an input parameter as some difference in the geometry representation of a spatial object is to be expected. The method generates matches between spatial objects using location information and lexical information, such as names and types, and verifies consistency of matches using reasoning in qualitative spatial and description logic. We test the method by matching geospatial data from OpenStreetMap and the national mapping agencies of Great Britain and France. We also analyze how the level of tolerance affects the precision and recall of matching results for the same geographic area using 12 different levels of tolerance within a range of 1 to 80 m. The generated matches show potential in helping enrich and update geospatial data.
    May 09, 2016   doi: 10.1111/tgis.12210   open full text
  • “Laser Discoverers” – Web‐based User‐generated Content in Heritage Detection in Poland.
    Krzysztof Stereńczak, Rafal Zapłata, Maciej Sztampke, Radomir Bałazy.
    Transactions in GIS. May 04, 2016
    This article presents the results and potential of using volunteered geographic information (VGI) in heritage detection. Research was completed under the project entitled “Laser Discoverers – non‐invasive examination and documentation of archeological and historical objects in the Świętokrzyskie Voivodeship”, carried out as a part of the Ministry of Science and Higher Education program entitled “The Paths of Copernicus”. Within the project, strong emphasis was placed on promotional and awareness‐raising activities, to involve as many voluntary users as possible. Project participants had at their disposal a web application, which provided access to a digital terrain model (DTM) where they identified possible heritage objects. All samples of data were additionally available in eight variants of sunshine, based on the simulation of sunlight from eight directions and at a constant angle. In total, 5,989 elementary areas with dimensions of 100 × 100 m were used for the project. After conducting a field inventory, Internet users together with specialists were able to recognize several thousands of potential archaeological and historic objects. During the project, approximately 10% of those features were verified through non‐invasive (field survey) work, with 75% success.
    May 04, 2016   doi: 10.1111/tgis.12206   open full text
  • Statistical Relational Learning of Grammar Rules for 3D Building Reconstruction.
    Youness Dehbi, Fabian Hadiji, Gerhard Gröger, Kristian Kersting, Lutz Plümer.
    Transactions in GIS. April 30, 2016
    The automatic interpretation of 3D point clouds for building reconstruction is a challenging task. The interpretation process requires highly structured models representing semantics. Formal grammars can describe structures as well as the parameters of buildings and their parts. We propose a novel approach for the automatic learning of weighted attributed context‐free grammar rules for 3D building reconstruction, supporting the laborious manual design of rules. We separate structure from parameter learning. Specific Support Vector Machines (SVMs) are used to generate a weighted context‐free grammar and predict structured outputs such as parse trees. The grammar is extended by parameters and constraints, which are learned based on a statistical relational learning method using Markov Logic Networks (MLNs). MLNs enforce the topological and geometric constraints. MLNs address uncertainty explicitly and provide probabilistic inference. They are able to deal with partial observations caused by occlusions. Uncertain projective geometry is used to deal with the uncertainty of the observations. Learning is based on a large building database covering different building styles and façade structures. In particular, a treebank that has been derived from the database is employed for structure learning.
    April 30, 2016   doi: 10.1111/tgis.12200   open full text
  • VGDI – Advancing the Concept: Volunteered Geo‐Dynamic Information and its Benefits for Population Dynamics Modeling.
    Christoph Aubrecht, Dilek Özceylan Aubrecht, Joachim Ungar, Sérgio Freire, Klaus Steinnocher.
    Transactions in GIS. April 29, 2016
    The concept of Volunteered Geographic Information (VGI) has progressed from being an exotic prospect to making a profound impact on GIScience and geography in general, as initially anticipated. However, while massive and manifold data is continuously produced voluntarily and applications are built for information and knowledge extraction, the initially introduced concept of VGI lacks certain methodological perspectives in this regard which have not been fully elaborated. In this article we highlight and discuss an important gap in this concept, i.e. the lack of formal acknowledgment of temporal aspects. By coining the proposed advanced framework ‘Volunteered Geo‐Dynamic Information’ (VGDI), we attempt to lay the ground for full conceptual and applied spatio‐temporal integration. To illustrate that integrative approach of VGDI and its benefits, we describe the potential impact on the field of dynamic population distribution modeling. While traditional approaches in that domain rely on survey‐based data and statistics as well as static geographic information, the use of VGDI enables a dynamic setup. Foursquare venue and user check‐in data are presented for a test site in Lisbon, Portugal. Two core modules of spatio‐temporal population assessment are thereby addressed, namely time use profiling and target zone characterization, motivated by the potential integration in existing population dynamics frameworks such as the DynaPop model.
    April 29, 2016   doi: 10.1111/tgis.12203   open full text
  • A User‐centered Design for the Addition of Interactive Masking Capability within an existing Web GIS.
    John D. Morgan.
    Transactions in GIS. April 29, 2016
    This article presents a case study of how a user‐centered design (UCD) approach was utilized during the addition of interactive masking capability to an existing web‐based geographic information system (Web GIS). By analyzing and discussing specific aspects of the user‐developer dialog within the context of a Web GIS software development life cycle, this article presents a case study for similar systems. The results of the UCD methodology is a discussion that presents a shift from an initial design to a new design that, based on user feedback, furthers the utility and usability of interactive masking within the Web GIS.
    April 29, 2016   doi: 10.1111/tgis.12197   open full text
  • Classifying Human Activity Patterns from Smartphone Collected GPS data: A Fuzzy Classification and Aggregation Approach.
    Neng Wan, Ge Lin.
    Transactions in GIS. April 12, 2016
    Smartphones have emerged as a promising type of equipment for monitoring human activities in environmental health studies. However, degraded location accuracy and inconsistency of smartphone‐measured GPS data have limited its effectiveness for classifying human activity patterns. This study proposes a fuzzy classification scheme for differentiating human activity patterns from smartphone‐collected GPS data. Specifically, a fuzzy logic reasoning was adopted to overcome the influence of location uncertainty by estimating the probability of different activity types for single GPS points. Based on that approach, a segment aggregation method was developed to infer activity patterns, while adjusting for uncertainties of point attributes. Validations of the proposed methods were carried out based on a convenient sample of three subjects with different types of smartphones. The results indicate desirable accuracy (e.g. up to 96% in activity identification) using of this method. Two examples are provided in the Appendix to illustrate how the proposed methods could be applied in environmental health studies. Researchers could tailor this scheme to fit a variety of research topics.
    April 12, 2016   doi: 10.1111/tgis.12181   open full text
  • Perceptions and Practices: Employers, Educators, and Students on GIS Internships.
    Thomas R. Craig, Thomas A. Wikle.
    Transactions in GIS. April 04, 2016
    Within an increasingly competitive job market, academic internships have become an important source of work experience for students with career interests involving geographic information systems (GIS) and related geospatial technologies. However, while GIS internships offer benefits to employers and students, their structure and objectives may be viewed differently across stakeholder groups such as private industry, government, and academia. In this article we evaluate how GIS internships are valued and perceived by employers, educators, and the interns themselves using quantitative and qualitative measures collected though web‐based surveys and semi‐structured telephone interviews. Data analysis helped us determine the relative importance of technical and non‐technical skills needed by students in preparation for GIS internships. Our findings reveal relatively few differences in scores assigned to technical and non‐technical skills when comparing employer and educator ratings. Educator ratings were higher for nearly all technical and non‐technical skills. In comparison, employers placed greater emphasis on technical skills involving data entry/manipulation and non‐technical skills such as flexibility/adaptability. The survey also revealed differences in employer and educator perceptions of internship goals and administration. Telephone surveys with former interns supplemented information from employer and educator surveys in developing “best practices” that may be useful in the design and administration of GIS internships.
    April 04, 2016   doi: 10.1111/tgis.12201   open full text
  • Using a WebMapping Platform to Engage Volunteers to Collect Data on Invasive Plants Distribution.
    Hélia Marchante, Maria Cristina Morais, Alexandre Gamela, Elizabete Marchante.
    Transactions in GIS. March 23, 2016
    WebMapping and citizen science are increasing their importance as tools both in science communication and in gathering abundant data. Nevertheless, gathering good and plentiful data from citizens when the scientific theme is unknown to them is a demanding challenge. is a science communication endeavor that targets the general public and one of its core elements is a WebMapping platform that intends to engage volunteers to geolocate invasive plants in Portugal. Besides gathering data for scientific research and to support management, the platform raises awareness about invasive plants. The platform has been available since March 2013 and receives data from a smartphone application and a Web application. Validated sightings are shown on an online map. All data is available through a Google Fusion Table and GBIF database (open data logic). Several strategies (interactive contents, printed materials, workshops and social media) were used to overcome the challenges of engaging contributors and making them better skilled to contribute with good data. After two years of steady growth in members (ca. 600) and sightings (>5400) the results are better than expected particularly amongst a population not familiarized with either citizen science or invasive plants. The outcomes of the platform and the efficacy of each strategy are analyzed and the accuracy and usefulness of the data are discussed.
    March 23, 2016   doi: 10.1111/tgis.12198   open full text
  • Limitations of Majority Agreement in Crowdsourced Image Interpretation.
    Carl F Salk, Tobias Sturn, Linda See, Steffen Fritz.
    Transactions in GIS. March 14, 2016
    Crowdsourcing can efficiently complete tasks that are difficult to automate, but the quality of crowdsourced data is tricky to evaluate. Algorithms to grade volunteer work often assume that all tasks are similarly difficult, an assumption that is frequently false. We use a cropland identification game with over 2,600 participants and 165,000 unique tasks to investigate how best to evaluate the difficulty of crowdsourced tasks and to what extent this is possible based on volunteer responses alone. Inter‐volunteer agreement exceeded 90% for about 80% of the images and was negatively correlated with volunteer‐expressed uncertainty about image classification. A total of 343 relatively difficult images were independently classified as cropland, non‐cropland or impossible by two experts. The experts disagreed weakly (one said impossible while the other rated as cropland or non‐cropland) on 27% of the images, but disagreed strongly (cropland vs. non‐cropland) on only 7%. Inter‐volunteer disagreement increased significantly with inter‐expert disagreement. While volunteers agreed with expert classifications for most images, over 20% would have been mis‐categorized if only the volunteers’ majority vote was used. We end with a series of recommendations for managing the challenges posed by heterogeneous tasks in crowdsourcing campaigns.
    March 14, 2016   doi: 10.1111/tgis.12194   open full text
  • A Genetic Algorithm for Tributary Selection with Consideration of Multiple Factors.
    Ling Zhang, Eric Guilbert.
    Transactions in GIS. March 14, 2016
    Drainage systems are important components in cartography and Geographic Information Systems (GIS), and achieve different drainage patterns based on the form and texture of their network of stream channels and tributaries due to local topography and subsurface geology. The drainage pattern can reflect the geographical characteristics of a river network to a certain extent. To preserve the drainage pattern during the generalization process, this article proposes a solution to deal with many factors, such as the tributary length and the order in river tributary selection. This leads to a multi‐objective optimization problem solved with a Genetic Algorithm. In the multi‐objective model, different weights are used to aggregate all objective functions into a fitness function. The method is applied on a case study to evaluate the importance of each factor for different types of drainage and results are compared with a manually generalized network. The result can be controlled by assigning different weights to the factors. From this work, different weight settings according to drainage patterns are proposed for the river network generalization.
    March 14, 2016   doi: 10.1111/tgis.12205   open full text
  • Building Information Modelling for High‐rise Land Administration.
    Behnam Atazadeh, Mohsen Kalantari, Abbas Rajabifard, Serene Ho, Tuan Ngo.
    Transactions in GIS. March 14, 2016
    Current land administration systems mainly use 2D plans to define and secure ownership rights associated with properties in high‐rise buildings. These 2D plans may not effectively communicate and manage the spatial complexity associated with multi‐layered and stacked properties in such buildings; additionally, multiple pages of plans (representing sections of the building) are required to represent all ownership boundaries. In response, land administration organizations have been investigating a 3D digital approach to managing information about ownership rights in high‐rise building structures. In this article, Building Information Modeling (BIM) is proposed as a feasible approach for managing land and property information in high‐rise buildings. BIM provides a collaborative, digital and intelligent 3D data environment for managing building information throughout the lifecycle of buildings. However, there is currently no capacity in BIM for recording and representing information about ownership and boundaries of properties, which is core land administration information. Therefore, this article proposes an extension to the BIM standard, which is implemented in a prototype BIM model of a complex building to showcase the potential capability of using BIM for high‐rise land administration and for modeling 3D ownership rights.
    March 14, 2016   doi: 10.1111/tgis.12199   open full text
  • Towards an Automated Comparison of OpenStreetMap with Authoritative Road Datasets.
    Maria Antonia Brovelli, Marco Minghini, Monia Molinari, Peter Mooney.
    Transactions in GIS. March 10, 2016
    OpenStreetMap (OSM) is an extraordinarily large and diverse spatial database of the world. Road networks are amongst the most frequently occurring spatial content within the OSM database. These road network representations are usable in many applications. However the quality of these representations can vary between locations. Comparing OSM road networks with authoritative road datasets for a given area or region is an important task in assessing OSM's fitness for use for applications like routing and navigation. Such comparisons can be technically challenging and no software implementation exists which facilitates them easily and automatically. In this article we develop and propose a flexible methodology for comparing the geometry of OSM road network data with other road datasets. Quantitative measures for the completeness and spatial accuracy of OSM are computed, including the compatibility of OSM road data with other map databases. Our methodology provides users with significant flexibility in how they can adjust the parameterization to suit their needs. This software implementation is exclusively built on open source software and a significant degree of automation is provided for these comparisons. This software can subsequently be extended and adapted for comparison between OSM and other external road datasets.
    March 10, 2016   doi: 10.1111/tgis.12182   open full text
  • Conflation of OpenStreetMap and Mobile Sports Tracking Data for Automatic Bicycle Routing.
    Cecilia Bergman, Juha Oksanen.
    Transactions in GIS. March 10, 2016
    This article investigates how workout trajectories from a mobile sports tracking application can be used to provide automatic route suggestions for bicyclists. We apply a Hidden Markov Model (HMM)‐based method for matching cycling tracks to a “bicycle network” extracted from crowdsourced OpenStreetMap (OSM) data, and evaluate its effective differences in terms of optimal routing compared with a simple geometric point‐to‐curve method. OSM has quickly established itself as a popular resource for bicycle routing; however, its high‐level of detail presents challenges for its applicability to popularity‐based routing. We propose a solution where bikeways are prioritized in map‐matching, achieving good performance; the HMM‐based method matched correctly on average 94% of the route length. In addition, we show that the extremely biased nature of the trajectory dataset, which is typical of volunteered user‐generated data, can be of high importance in terms of popularity‐based routing. Most computed routes diverged depending on whether the number of users or number of tracks was used as an indicator of popularity, which may imply varying preferences among different types of cyclists. Revising the number of tracks by diversity of users to surmount local biases in the data had a more limited effect on routing.
    March 10, 2016   doi: 10.1111/tgis.12192   open full text
  • A Spatial Conditioned Latin Hypercube Sampling Method for Mapping Using Ancillary Data.
    Bingbo Gao, Yuchun Pan, Ziyue Chen, Fang Wu, Xuhong Ren, Maogui Hu.
    Transactions in GIS. March 10, 2016
    For obtaining maps of good precision by the spatial inference method, the distribution of sampling sites in geographical and feature space is very important. For a regional variable with trends, the predicting error comes from trend estimation, variogram estimation and spatial interpolation. Based on the cLHS (conditioned Latin hypercube Sampling) method, a sampling method called scLHS (spatial cLHS) considering all these three aspects with the help of ancillary data is proposed in this article. Its advantage lies in simultaneously improving trend estimation, variogram estimation and spatial interpolation. MODIS data and simulated data were used as sampling fields to draw sample sets using scLHS, cLHS, cLHS with x and y coordinates as covariates, simple random and spatial even sampling methods, and the distribution and prediction errors of sample sets from different methods were evaluated. The results showed that scLHS performed well in balancing spreading in geographic and feature space, and can generate points pairs with small distances, and the sample sets drawn by scLHS produced smaller mapping error, especially when there were trends in the target variable.
    March 10, 2016   doi: 10.1111/tgis.12176   open full text
  • High Resolution Köppen‐Geiger Classifications of Paleoclimate Simulations.
    Christian Willmes, Daniel Becker, Sebastian Brocks, Christoph Hütt, Georg Bareth.
    Transactions in GIS. March 10, 2016
    The development and application of an algorithm to compute Köppen‐Geiger climate classifications from the Coupled Model Intercomparison Project (CMIP) and Paleo Model Intercomparison Project (PMIP) climate model simulation data is described in this study. The classification algorithm was applied to data from the PMIP III paleoclimate experiments for the Last Glacial Maximum, 21k years before present (yBP), Mid‐Holocene (6k yBP) and the Pre‐Industrial (0k yBP, control run) time slices. To infer detailed classification maps, the simulation datasets were interpolated to a higher resolution. The classification method presented is based on the application of Open Source Software, and the implementation is described with attention to detail. The source code and the exact input data sets as well as the resulting data sets are provided to enable the application of the presented approach.
    March 10, 2016   doi: 10.1111/tgis.12187   open full text
  • How Officers Create Guardianship: An Agent‐based Model of Policing.
    Sarah C. Wise, Tao Cheng.
    Transactions in GIS. March 09, 2016
    Crime is a complex phenomenon, emerging from the interactions of offenders, victims, and their environment, and in particular from the presence or absence of capable guardians. Researchers have historically struggled to understand how police officers create guardianship. This presents a challenge because, in order to understand how to advise the police, researchers must have an understanding of how the current system works. The work presents an agent‐based model that simulates the movement of police vehicles, using a record of real calls for service and real levels of police staffing in spatially explicit environments to emulate the demands on the police force. The GPS traces of the simulated officers are compared with real officer movement GPS data in order to assess the quality of the generated movement patterns. The model represents an improvement on existing standards of police simulation, and points the way toward more nuanced understandings of how police officers influence the criminological environment.
    March 09, 2016   doi: 10.1111/tgis.12173   open full text
  • Identification and Modelling of Translational and Axial Symmetries and their Hierarchical Structures in Building Footprints by Formal Grammars.
    Youness Dehbi, Gerhard Gröger, Lutz Plümer.
    Transactions in GIS. February 09, 2016
    Buildings and other man‐made objects, for many reasons such as economical or aesthetic, are often characterized by their symmetry. The latter predominates in the design of building footprints and building parts such as façades. Thus the identification and modeling of this valuable information facilitates the reconstruction of these buildings and their parts. This article presents a novel approach for the automatic identification and modelling of symmetries and their hierarchical structures in building footprints, providing an important prior for façade and roof reconstruction. The uncertainty of symmetries is explicitly addressed using supervised machine learning methods, in particular Support Vector Machines (SVMs). Unlike classical statistical methods, for SVMs assumptions on the a priori distribution of the data are not required. Both axial and translational symmetries are detected. The quality of the identified major and minor symmetry axes is assessed by a least squares based adjustment. Context‐free formal grammar rules are used to model the hierarchical and repetitive structure of the underlying footprints. We present an algorithm which derives grammar rules based on the previously acquired symmetry information and using lexical analysis describing regular patterns and palindrome‐like structures. This offers insights into the latent structures of building footprints and therefore describes the associated façade in a relational and compact way.
    February 09, 2016   doi: 10.1111/tgis.12177   open full text
  • SPAWNN: A Toolkit for SPatial Analysis With Self‐Organizing Neural Networks.
    Julian Hagenauer, Marco Helbich.
    Transactions in GIS. February 02, 2016
    This article introduces the SPAWNN toolkit, an innovative toolkit for spatial analysis with self‐organizing neural networks, which is published as free and open‐source software ( It extends existing toolkits in three important ways. First, the SPAWNN toolkit distinguishes between self‐organizing neural networks and spatial context models with which the networks can be combined to incorporate spatial dependence and provides implementations for both. This distinction maintains modularity and enables a multitude of useful combinations for analyzing spatial data with self‐organizing neural networks. Second, SPAWNN interactively links different self‐organizing networks and data visualizations in an intuitive manner to facilitate explorative data analysis. Third, it implements cutting‐edge clustering algorithms for identifying clusters in the trained networks. Toolkits such as SPAWNN are particularly needed when researchers and practitioners are confronted with large amounts of complex and high‐dimensional data. The computational performance of the implemented algorithms is empirically demonstrated using high‐dimensional synthetic data sets, while the practical functionality highlighting the distinctive features of the toolkit is illustrated with a case study using socioeconomic data of the city of Philadelphia, Pennsylvania.
    February 02, 2016   doi: 10.1111/tgis.12180   open full text
  • Integrating Indoor and Outdoor Spaces for Pedestrian Navigation Guidance: A Review.
    Ann Vanclooster, Nico Van de Weghe, Philippe De Maeyer.
    Transactions in GIS. February 02, 2016
    In light of the many improvements within 3D urban modeling and Location‐Based Services, this article provides a timely review of the state‐of‐the‐art on integrating indoor and outdoor spaces in pedestrian navigation guidance aids. With people moving seamlessly between buildings and surrounding areas, navigation guidance tools should extend from merely outdoor or indoor guidance, to provide support in the combined indoor‐outdoor context. This article first examines the challenges and complexities of integrating indoor and outdoor spaces into a single navigation system. Next, by using objective selection criteria, 36 relevant studies were withheld and further reviewed on their specific developments in data model requirements, and algorithmic and context support for integrated IO navigation systems. This review shows that the challenges of dealing with both indoor and outdoor space structures, while taking into account pedestrian's freer use of space, currently complicate the proposition of a unified IO space concept for navigation. However, there are some ongoing developments (e.g. context definitions, algorithmic extensions, increased data availability, growing awareness of pedestrians’ perception during wayfinding) that will help to bring outdoor and indoor spaces closer together in the realm of combined geospatial analysis.
    February 02, 2016   doi: 10.1111/tgis.12178   open full text
  • Progressive Visualization of Complex 3D Models Over the Internet.
    Jing Chen, Jiawei Li, Mo Li.
    Transactions in GIS. February 01, 2016
    The online transmission and real‐time rendering of complex 3D models have always been a bottleneck which limits the performance of Web 3D simulation systems. To improve the efficiency of data transmission and mesh reconstruction, this article proposes a novel progressive mesh structure. In the first stage of progressive visualization, the base data and the base index generated by vertex clustering simplification are transmitted to the client for the fundamental rendering. Then the incremental data and corresponding indexes at higher levels are transmitted, as the viewpoint approaches the simulation object. The multi‐scale incremental data organization benefits the performance and efficiency of the Web 3D simulation system by separately transmitting and reconstructing the corresponding level of mesh details. To demonstrate the adaptability and reliability of this algorithm, we developed an experimental prototype system to conduct a series of experiments. The results of experiments show that the improved progressive mesh structure described in this article takes good advantage of the vertex clustering simplification scheme to increase the efficiency of online transmission and mesh reconstruction, and the average frame rate of the progressive visualization has been increased to some extent, especially for massive data in large scale scenes.
    February 01, 2016   doi: 10.1111/tgis.12185   open full text
  • Automatic Update of Road Attributes by Mining GPS Tracks.
    Karl van Winden, Filip Biljecki, Stefan van der Spek.
    Transactions in GIS. January 25, 2016
    Despite advances in cartography, mapping is still a costly process which involves a substantial amount of manual work. This article presents a method for automatically deriving road attributes by analyzing and mining movement trajectories (e.g. GPS tracks). We have investigated the automatic extraction of eight road attributes: directionality, speed limit, number of lanes, access, average speed, congestion, importance, and geometric offset; and we have developed a supervised classification method (decision tree) to infer them. The extraction of most of these attributes has not been investigated previously. We have implemented our method in a software prototype and we automatically update the OpenStreetMap (OSM) dataset of the Netherlands, increasing its level of completeness. The validation of the classification shows variable levels of accuracy, e.g. whether a road is a one‐ or a two‐way road is classified with an accuracy of 99%, and the accuracy for the speed limit is 69%. When taking into account speed limits that are one step away (e.g. 60 km/h instead of the classified 50 km/h) the classification increases to 95%, which might be acceptable in some use‐cases. We mitigate this with a hierarchical code list of attributes.
    January 25, 2016   doi: 10.1111/tgis.12186   open full text
  • The Scale of VGI in Map Production: A Perspective on European National Mapping Agencies.
    Ana‐Maria Olteanu‐Raimond, Glen Hart, Giles M. Foody, Guillaume Touya, Tobias Kellenberger, Demetris Demetriou.
    Transactions in GIS. January 25, 2016
    The perspective of European National Mapping Agencies (NMA) on the role of citizen sensing in map production was explored. The NMAs varied greatly in their engagement with the community generating volunteered geographic information (VGI) and in their future plans. From an assessment of NMA standard practices, it was evident that much VGI was acquired with a positional accuracy that, while less than that typically acquired by NMAs, actually exceeded the requirements of the nominal data capture scale used by most NMAs. Opportunities for VGI use in map revision and updating were evident, especially for agencies that use a continuous rather than cyclical updating policy. Some NMAs had also developed systems to engage with citizen sensors and examples are discussed. Only rarely was VGI used to collect data on features beyond the standard set used by the NMAs. The potential role of citizen sensing and so its current scale of use by NMAs is limited by a series of concerns, notably relating to issues of data quality, the nature and motivation of the contributors, legal issues, the sustainability of data source, and employment fears of NMA staff. Possible priorities for future research and development are identified to help ensure that the potential of VGI in mapping is realized.
    January 25, 2016   doi: 10.1111/tgis.12189   open full text
  • User Contribution Patterns and Completeness Evaluation of Mapillary, a Crowdsourced Street Level Photo Service.
    Levente Juhász, Hartwig H. Hochmair.
    Transactions in GIS. January 25, 2016
    Mapillary is a Web 2.0 application which allows users to contribute crowdsourced street level photographs from all over the world. In the first part of the analysis this article reviews Mapillary data growth for continents and countries as well as the contribution behavior of individual mappers, such as the number of days of active mapping. In the second part of the analysis the study assesses Mapillary data completeness relative to a reference road network dataset at the country level. In addition, a more detailed completeness analysis is conducted for selected urban and rural areas in the US and part of northern Europe for which the completeness of Mapillary data will also be compared with that of Google Street View. Results show that Street View provides generally a better coverage on almost all road categories with some exceptions for pedestrian and cycle paths in selected cities. However, Mapillary data can be conveniently collected from any mobile device that is equipped with a photo camera. This gives Mapillary the potential to reach better coverage along off‐road segments than Google Street View.
    January 25, 2016   doi: 10.1111/tgis.12190   open full text
  • Similarity Measurements on Multi‐Scale Qualitative Locations.
    Shihong Du, Luo Guo.
    Transactions in GIS. January 24, 2016
    Qualitative representation of spatial locations and their similarity measurements are essential for the analysis of linguistic term‐based data. Existing methods have focused on the similarities of spatial relations and spatial scenes but have not considered the variations in geometrical representations and relations over scales. This study developed some new measures to assess the similarities of both single‐ and multi‐scale qualitative locations. Region‐ and cell‐based models were used to formalize qualitative locations of spatial objects with respect to multi‐scale frames of reference. The similarities were assessed by integrating the similarities of frames and qualitative relations. The frame similarity measures how two objects are compared considering the common elements that they occupy in the reference frames. Moreover, the similarity of qualitative relation measures how two relations relate two objects to the corresponding elements in the frames. The location similarities at a single level integrate the similarities of the frames and qualitative relations, whereas the location similarities at multiple scales incorporate the variations in qualitative locations over scales. These methods were used to assess location similarities concerning residential areas, roads, and lakes. The results indicated that the location‐based measurements can disclose the distributions of the similarities and that the cell‐based model is more accurate than the region‐based model.
    January 24, 2016   doi: 10.1111/tgis.12179   open full text
  • A Topology‐Inferred Graph‐Based Heuristic Algorithm for Map Simplification.
    QiuLei Guo, Hassan A. Karimi.
    Transactions in GIS. January 05, 2016
    In this article we present a heuristic map simplification algorithm based on a novel topology‐inferred graph model. Compared with the existing algorithms, which only focus either on geometry simplification or on topological consistency, our algorithm simplifies the map composed of series of polylines and constraint points while maintaining the topological relationships in the map, maximizing the number of removal points, and minimizing error distance efficiently. Unlike some traditional geometry simplification algorithms, such as Douglas and Peucker's, which add points incrementally, we remove points sequentially based on a priority determined by heuristic functions. In the first stage, we build a graph to model the topology of points in the map from which we determine whether a point is removable or not. As map generalization is needed in different applications with different requirements, we present two heuristic functions to determine the priority of points removal for two different purposes: to save storage space and to reduce computation time. The time complexity of our algorithm is O(nlogk) which is efficient enough to be considered for real‐time applications. Experiments on real maps were conducted and the results indicate that our algorithm produces high quality results; one heuristic function results in higher removal points saving storage space and the other improves the time performance significantly.
    January 05, 2016   doi: 10.1111/tgis.12188   open full text
  • Geo‐questionnaire: A Method and Tool for Public Preference Elicitation in Land Use Planning.
    Piotr Jankowski, Michał Czepkiewicz, Marek Młodkowski, Zbigniew Zwoliński.
    Transactions in GIS. January 05, 2016
    Geo‐questionnaire involves an integration of sketchable maps with questions, aimed at eliciting public preferences and attitudes about land allocation and services. Respondents can link their answers with corresponding locations on a map by marking points or sketching polygon features. Geo‐questionnaires have been used to learn about perceptions and preferences of city residents for specific types of land use, place‐based services, and development projects. This article reports on results of an empirical study, in which an online geo‐questionnaire was designed and implemented to elicit preferences of residents in guiding an urban development plan. Preferences collected in the form of polygon sketches were processed using GIS operations and mapped for visual interpretation. The article focuses on aggregation and analysis of respondent preferences including the analysis of positional and attribute uncertainty. Results of the study show that geo‐questionnaire is a scalable method for eliciting public preferences with a potential for meaningfully informing land use planning.
    January 05, 2016   doi: 10.1111/tgis.12191   open full text
  • Comparison of Kernel Density and Local Convex Hull Methods for Assessing Distribution Ranges of Large Mammalian Herbivores.
    George J Chirima, Norman Owen‐Smith.
    Transactions in GIS. January 05, 2016
    When assessing distribution range shifts, precise information is required on distribution limits, densities in occupied regions, unoccupied gaps, and changes in these measures over time. The local convex hull method recently developed for home range delineation to provide these measures was compared with that of the widely applied parametric kernel density estimation and with the commonly used tile method. The assessment used location records from 14 years of aerial surveys on four mammalian herbivores selected because of their distinct distribution patterns. Impala showed an almost continuous distribution with few gaps, wildebeest a wide distribution with regional concentrations, waterbuck a linear distribution along rivers, and sable antelope a widespread but patchy distribution. The kernel method tended to extend ranges beyond observed records, obscuring gaps within distributions. With parametric kernel approaches, bandwidth obtained via Least Squares Cross Validation techniques was not optimal when the local abundance was widely disparate, as was the case for wildebeest. The LoCoH method most effectively revealed meaningful gaps. The LoCoH method is advantageous for precisely mapping the distributions of conspicuous species for which the absence of records indicates true gaps in occurrence.
    January 05, 2016   doi: 10.1111/tgis.12193   open full text
  • Advancing Science with VGI: Reproducibility and Replicability of Recent Studies using VGI.
    Frank O. Ostermann, Carlos Granell.
    Transactions in GIS. January 05, 2016
    In scientific research, reproducibility and replicability are requirements to ensure the advancement of our body of knowledge. This holds true also for VGI‐related research and studies. However, the characteristics of VGI suggest particular difficulties in ensuring reproducibility and replicability. In this article, we aim to examine the current situation in VGI‐related research, and identify strategies to ensure realization of its full potential. To do so, we first investigate the different aspects of reproducibility and replicability and their impact on VGI‐related research. These impacts are different depending on the objectives of the study. Therefore, we examine the study focus of VGI‐related research to assess the current body of research and structure our assessment. This work is based on a rigorous review of the elements of reproducibility and a systematic mapping and analysis of 58 papers on the use of VGI in the crisis management field. Results of our investigation show that reproducibility issues related to data are a serious concern, while reproducibility issues related to analysis methods and processes face fewer challenges. However, since most studies still focus on analyzing the source data, reproducibility and replicability are still an unsolved problem in VGI‐related research. Therefore, we show initiatives tackling the problem, and finally formulate strategies to improve the situation.
    January 05, 2016   doi: 10.1111/tgis.12195   open full text
  • Video Data Model and Retrieval Service Framework Using Geographic Information.
    Zhigang Han, Caihui Cui, Yunfeng Kong, Fen Qin, Pinde Fu.
    Transactions in GIS. December 28, 2015
    Along with a rapid growth in the volume of user‐generated video clips, efficient video retrieval methods have become one of the most critical challenges in multimedia management. In this article, we propose a service framework using geographic information for retrieval of the videos on the web. The main idea is to describe and query videos by video‐related geographic data such as video location, field of view and trajectory. Based on the point, line and polygon description for videos, we define the commonly used video retrieval methods. A video retrieval service framework and the service interfaces are designed based on the REST architecture. A prototype system is also implemented to test the services. The experiment shows that the proposed video description, retrieval methods and web services are feasible and useful. We believe that the integration of geographical video retrieval methods into existing methods will promote the geo‐tagged video sharing, discovery and consumption in various web applications.
    December 28, 2015   doi: 10.1111/tgis.12175   open full text
  • Modeling Urban Land Use Changes Using Support Vector Machines.
    Mileva Samardžić‐Petrović, Suzana Dragićević, Miloš Kovačević, Branislav Bajat.
    Transactions in GIS. November 26, 2015
    Support Vector Machines (SVM) is a machine learning (ML) algorithm commonly applied to the classification of remotely sensing data and more recently for modeling land use changes. However, in most geospatial applications the current literature does not elaborate on specifications of the SVM method with respect to data sampling, attribute selection and optimal parameters choices. Therefore the main objective of this study is to present and investigate the SVM technique for modeling urban land use change. The SVM model building procedure is presented together with the detailed evaluation of the output results with respect to the choice of datasets, attributes and the change of SVM parameters. Geospatial datasets containing nine land use classes and spatial attributes for the Municipality of Zemun, Republic of Serbia were used for years 2001, 2003, 2007 and 2011. The Correlation‐based Feature Subset method, kappa coefficient, Area Under Receiver Operating Characteristic Curve (AUC) and kappa simulation were used to perform the model evaluation and compare the model outputs with the real land use datasets. The obtained results indicate that the SVM‐based models perform better when implementing balanced data sampling, reduced data sets to informative subsets of attributes and properly identify the optimal learning parameters.
    November 26, 2015   doi: 10.1111/tgis.12174   open full text
  • Assessing Resistance to Volunteered Geographic Information Reporting within Local Government.
    Muning W. Brandeis, Timothy Nyerges.
    Transactions in GIS. November 02, 2015
    Using volunteered geographic information (VGI) as a cost‐saving environmental monitoring and public participation mechanism has been thought to be a proof of concept to assist environmental decision‐making with insufficient managerial resources. However, research literature also often found institutional resistance when implementing VGI as part of the decision‐making process. This research develops a conceptual framework as the foundation to conduct a cross‐case comparison for four empirical cases in recreation and invasive species monitoring, but general enough for other such case comparisons. The VGI Reporting Assessment Framework (VGI‐RAF) adopted aspects of the Decision Situation Assessment (DSA) framework as the foundation to address institutional flexibility, stakeholder dynamics, and technical considerations. Using a cross‐case comparison can accumulate deep observations from cases and increase validity of insights through comparing processes. Results show that eight aspects of the VGI‐RAF reveal the suitability of embedding voluntary information within existing institutional decision‐making processes. VGI‐RAF depicts considerations for: (1) existing participation arrangements, (2) institutional arrangements, (3) managers’ needs and stakeholder expectation, and (4) interaction mechanism and technical needs. The cross‐comparison results indicate that a public participation mechanism should be accompanied by VGI development to increase effectiveness. Institutional arrangements should match local government's information needs with participants’ expectations. Knowledge gaps between institutional information needs and volunteer knowledge should be filled through technology enhancements. For ease of implementation and to promote long‐term success, we recommend that volunteered information be connected with existing communication channels to minimize changes to existing information systems.
    November 02, 2015   doi: 10.1111/tgis.12168   open full text
  • An Immune Genetic Algorithm to Buildings Displacement in Cartographic Generalization.
    Yageng Sun, Qingsheng Guo, Yuangang Liu, Xiaoya Ma, Jie Weng.
    Transactions in GIS. October 23, 2015
    Spatial conflicts may occur when map data are displayed at a scale smaller than that of the source map. This study applies the displacement operator in cartographic generalization to resolve such spatial conflicts and to improve the clarity and legibility of map. The immune genetic algorithm (IGA) is used in this study for buildings displacement to solve conflicts. IGA is based on the genetic algorithm (GA) and employs the self‐adjusting mechanism of antibody concentration to enhance population diversity. Meanwhile, the elitism retention strategy is adopted in IGA to guarantee that the best individual (antibody) is not lost and destroyed in the next generation to strengthen convergence efficiency. The compared experiment between IGA and GA shows that the displacement result produced by IGA performs better than GA. Finally, in order to make the displaced map more attractive to cartographers, two constraints – the building alignment constraint and building tangent relation constraint – are applied in IGA to restrict the buildings’ displacement. The same experimental data are adopted to prove that the improved IGA is useful for maintaining the two constraints.
    October 23, 2015   doi: 10.1111/tgis.12165   open full text
  • A Spatial Data Infrastructure Approach for the Characterization of New Zealand's Groundwater Systems.
    Alexander Kmoch, Hermann Klug, Alistair B. H. Ritchie, Jochen Schmidt, Paul A. White.
    Transactions in GIS. October 23, 2015
    The future information needs of stakeholders for hydrogeological and hydro‐climate data management and assessment in New Zealand may be met with an Open Geospatial Consortium (OGC) standards‐compliant publicly accessible web services framework which aims to provide integrated use of groundwater information and environmental observation data in general. The stages of the framework development described in this article are search and discovery as well as data collection and access with (meta)data services, which are developed in a community process. The concept and prototype implementation of OGC‐compliant web services for groundwater and hydro‐climate data include demonstration data services that present multiple distributed datasets of environmental observations. The results also iterate over the stakeholder community process and the refined profile of OGC services for environmental observation data sharing within the New Zealand Spatial Data Infrastructure (SDI) landscape, including datasets from the National Groundwater Monitoring Program and the New Zealand Climate Database along with datasets from affiliated regional councils at regional‐ and sub‐regional scales. With the definition of the New Zealand observation data profile we show that current state‐of‐the‐art standards do not necessarily need to be improved, but that the community has to agree upon how to use these standards in an iterative process.
    October 23, 2015   doi: 10.1111/tgis.12171   open full text
  • Revealing Uncertainties in Land Change Modeling Using Probabilities.
    Carsten Krüger, Tobia Lakes.
    Transactions in GIS. October 09, 2015
    Land change models are frequently used to analyze current land change processes and possible future developments. However, the outcome of such models is accompanied by uncertainties that have to be taken into account in order to address their reliability for science and decision‐making. While a range of approaches exist that quantify the disagreement of land change maps, the quantification of uncertainty remains a major challenge. The aim of this article is therefore to reveal uncertainties in land change modeling by developing two measures: quantity uncertainty and allocation uncertainty. We choose a Bayesian Belief Network modeling approach for deforestation in Brazil to develop and apply the two measures to the resulting probability surface. Quantity uncertainty describes the uncertainty about the correct number of cells in a land change map assigned to different land change categories and allocation uncertainty expresses the uncertainty about the correct spatial placement of a cell in the land change map. Thus, uncertainty can be quantified even in those cases where no reference data exist. Informing about uncertainty in probabilistic outcomes may be an important asset when land change projections are being used in science and decision‐making and moreover, they may also be further evaluated for other spatial applications.
    October 09, 2015   doi: 10.1111/tgis.12161   open full text
  • ACSEBUL: An Approach for the Construction of Spatial Entities Based on Unified Logic.
    Renzhong Guo, Changbin Yu, Lin Li, Zhigang Zhao, Biao He.
    Transactions in GIS. October 06, 2015
    Approaches for automatically constructing 2D entities (e.g. 2D polygons) using 1D entities (e.g. 1D edges) have been widely discussed. However, few studies have considered how to construct 3D entities using lower‐dimensional entities, and fundamental research comparing 2D with 3D construction is even lacking. Therefore, this article proposes the Approach for Construction of Spatial Entities Based on Unified Logic (ACSEBUL), which can be applied to both 2D and 3D situations and can guarantee validation of these constructed 2D (3D) entities. Detailed definitions of the primitives and descriptions of ACSEBUL are provided, and typical 2D and 3D examples are shown. Furthermore, example experiments are performed using 2D and 3D parcels in Shenzhen, China. The results demonstrate that the 2D and 3D ACSEBUL methods, which are based on unified logic, can be used to automatically construct 2D and 3D entities, respectively.
    October 06, 2015   doi: 10.1111/tgis.12169   open full text
  • Assessing Raster GIS Approximation for Euclidean Shortest Path Routing.
    Insu Hong, Alan T. Murray.
    Transactions in GIS. September 24, 2015
    Identifying a route that avoids obstacles in continuous space is important for infrastructure alignment, robotic travel, and virtual object path planning, among others, because movement through space is not restricted to a predefined road or other network. Vector and raster GIS (geographic information system) solution approaches have been developed to find good/efficient routes. On the vector side, recent solution approaches exploit spatial knowledge and utilize GIS functionality, offering significant computational advantages in finding an optimal solution to this path routing problem. Raster‐based shortest path techniques are widely applied in route planning for wayfinding, corridor alignment, robotics and video gaming to derive an obstacle avoiding path, but represent an approximation approach for solving this problem. This research compares vector and raster approaches for identifying obstacle‐avoiding shortest paths/routes. Empirical assessment is carried out for a number of planning applications, highlighting representational issues, computational requirements and resulting path efficiency.
    September 24, 2015   doi: 10.1111/tgis.12160   open full text
  • Automatic conversion of IFC datasets to geometrically and semantically correct CityGML LOD3 buildings.
    Sjors Donkers, Hugo Ledoux, Junqiao Zhao, Jantien Stoter.
    Transactions in GIS. September 16, 2015
    Although the international standard CityGML has five levels of detail (LODs), the vast majority of available models are the coarse ones (up to LOD2, i.e. block‐shaped buildings with roofs). LOD3 and LOD4 models, which contain architectural details such as balconies, windows and rooms, rarely exist because, unlike coarser LODs, their construction requires several datasets that must be acquired with different technologies, and often extensive manual work is needed. In this article we investigate an alternative to obtaining CityGML LOD3 models: the automatic conversion from already existing architectural models (stored in the IFC format). Existing conversion algorithms mostly focus on the semantic mappings and convert all the geometries, which yields CityGML models having poor usability in practice (spatial analysis, for instance, is not possible). We present a conversion algorithm that accurately applies the correct semantics from IFC models and that constructs valid CityGML LOD3 buildings by performing a series of geometric operations in 3D. We have implemented our algorithm and we demonstrate its effectiveness with several real‐world datasets. We also propose specific improvements to both standards to foster their integration in the future.
    September 16, 2015   doi: 10.1111/tgis.12162   open full text
  • Optimal Routefinding Across Landscapes Featuring High‐cost Linear Obstacles.
    Denis J. Dean, Vaishnavi Thakar, Neeraj Sirdeshmukh.
    Transactions in GIS. September 11, 2015
    Existing GIS‐based least‐cost routefinding approaches can in some cases be confounded by linear features in the landscape whose crossing costs are high relative to other traversing costs found throughout the landscape. Unfortunately, such high‐cost linear features are not uncommon; they frequently occur in the form of hydrologic features whose crossing costs are high relative to costs of traversing the surrounding dry land. This study (1) enumerates the situations where existing approaches can fail, (2) proposes a simple method for overcoming the limitations of the existing approaches, and (3) conducts an experiment to assess the impact of the weaknesses of existing approaches and the magnitude of the differences between the results produced by existing and revised approaches. Our results show that in mountainous terrain, linear hydrologic features with high crossing costs can have a profound impact on least‐cost routes, and the choice of solution method has equally profound impacts on the optimal route produced by the analysis.
    September 11, 2015   doi: 10.1111/tgis.12170   open full text
  • Knowledge Transfer for Large‐Scale Urban Growth Modeling Based on Formal Concept Analysis.
    Jinyao Lin, Xia Li.
    Transactions in GIS. August 26, 2015
    Cellular automata (CA) are useful for studies on urban growth and land‐use changes. Although various methods have been developed to define transition rules, modeling urban growth of large areas remains a tough challenge owing to heterogeneous geographical features. To address the problem, we present a novel method based on the combination of Formal Concept Analysis (FCA) and knowledge transfer techniques. FCA is used to solicit association rules among cities within a large area. This method can provide a theoretical basis for the knowledge transfer process. A cutting‐edge algorithm called TrAdaBoost is then integrated with the commonly‐used Logistic‐CA as the modeling framework. The proposed method is applied to the urban growth modeling of Guangdong Province, a large region with 21 cities in China, from 2005 to 2008. Compared with traditional methods, this method can achieve better results at the provincial and local levels, according to the experiments. The combination of FCA and knowledge transfer is expected to provide a useful tool for calibrating large‐scale urban CA models.
    August 26, 2015   doi: 10.1111/tgis.12172   open full text
  • Hyperspectral Remote Sensing Classifications: A Perspective Survey.
    D Chutia, D K Bhattacharyya, K K Sarma, R Kalita, S Sudhakar.
    Transactions in GIS. August 07, 2015
    Classification of hyperspectral remote sensing data is more challenging than multispectral remote sensing data because of the enormous amount of information available in the many spectral bands. During the last few decades, significant efforts have been made to investigate the effectiveness of the traditional multispectral classification approaches on hyperspectral data. Formerly extensively established conventional classification methods have been dominated by the advanced classification approaches and many pre‐processing techniques have been developed and incorporated in hyperspectral classification. A perspective survey of hyperspectral remote sensing classification approaches is presented here. It comprehensively highlights the taxonomy of major classification approaches reported during the last two decades and describes an experimental evaluation of a few major classification algorithms. Recent advancements in the development of classification approaches are also emphasized with a set of guidelines for achieving better classification performances.
    August 07, 2015   doi: 10.1111/tgis.12164   open full text
  • Multidimensional Similarity Measuring for Semantic Trajectories.
    Andre Salvaro Furtado, Despina Kopanaki, Luis Otavio Alvares, Vania Bogorny.
    Transactions in GIS. July 27, 2015
    Most existing approaches aiming at measuring trajectory similarity are focused on two‐dimensional sequences of points, called raw trajectories. However, recent proposals have used background geographic information and social media data to enrich these trajectories with a semantic dimension, giving rise to the concept of semantic trajectories. Only a few works have proposed similarity measures for semantic trajectories or multidimensional sequences, having limitations such as predefined weight of the dimensions, sensitivity to noise, tolerance for gaps with different sizes, and the prevalence of the worst dimension similarity. In this article we propose MSM, a novel similarity measure for multidimensional sequences that overcomes the aforementioned limitations by considering and weighting the similarity in all dimensions. MSM is evaluated through an extensive experimental study that, based on a seed trajectory, creates sets of semantic trajectories with controlled transformations to introduce different kinds and levels of dissimilarity. For each set, we compute the similarity between the seed and the transformed trajectories, using different measures. The results showed that MSM was more robust and efficient than related approaches in the domain of semantic trajectories.
    July 27, 2015   doi: 10.1111/tgis.12156   open full text
  • The network K‐function in context: examining the effects of network structure on the network K‐function.
    David S. Lamb, Joni A. Downs, Chanyoung Lee.
    Transactions in GIS. July 27, 2015
    The flaws of using traditional planar point‐pattern analysis techniques with network constrained points have been thoroughly explored in the literature. Because of this, new network‐based measures have been introduced for their planar analogues, including the network based K‐function. These new measures involve the calculation of network distances between point events rather than traditional Euclidean distances. Some have suggested that the underlying structure of a network, such as whether it includes directional constraints or speed limits, may be considered when applying these methods. How different network structures might affect the results of the network spatial statistics is not well understood. This article examines the results of network K‐functions when taking into consideration network distances for three different types of networks: the original road network, topologically correct networks, and directionally constrained networks. For this aim, four scenarios using road networks from Tampa, Florida and New York City, New York were used to test how network constraints affected the network K‐function. Depending on which network is under consideration, the underlying network structure could impact the interpretation. In particular, directional constraints showed reduced clustering across the different scenarios. Caution should be used when selecting the road network, and constraints, for a network K‐function analysis.
    July 27, 2015   doi: 10.1111/tgis.12157   open full text
  • An Extension Mechanism to Verify, Constrain and Enhance Geoprocessing Workflows Invocation.
    Kunlun Qi, Zhipeng Gui, Zhenqiang Li, Wei Guo, Huayi Wu, Jianya Gong.
    Transactions in GIS. July 22, 2015
    Geospatial web service composition is a promising means for processing and analyzing geospatial data in distributed computing environments. However, convenient and effective approaches for assisting the invocation of geoprocessing workflows are still missing. Invocation errors frustrate users and eventually impact the popularity and application of geoprocessing workflows due to their complexity, inadequate description, constraints, and prompts for input/output parameters, workflow models, and their components. This article proposes an extension method for easy invocation of geoprocessing workflows to solve these problems. The proposed method facilitates the generation of Graphical User Interfaces (GUIs) and invocation messages, for human‐computer interaction and client‐workflow interaction respectively, by supplementing verification and constraints for workflow descriptions. Furthermore, by providing descriptive information, constraint mechanisms, and visualization functions, this approach enhances human‐computer interactivity during invocation. An exemplary user case demonstrates the feasibility of the method.
    July 22, 2015   doi: 10.1111/tgis.12152   open full text
  • Geometric Algebra Model for Geometry‐oriented Topological Relation Computation.
    Zhaoyuan Yu, Wen Luo, Linwang Yuan, Yong Hu, A‐xing Zhu, Guonian Lü.
    Transactions in GIS. July 03, 2015
    Classical topological relation expressions and computations are primarily based on abstract algebra. In this article, the representation and computation of geometry‐oriented topological relations (GOTR) are developed. GOTR is the integration of geometry and topology. The geometries are represented by blades, which contain both algebraic expressions and construction structures of the geometries in the conformal geometric algebra space. With the meet, inner, and outer products, two topology operators, the MeetOp and BoundOp operators, are developed to reveal the disjoint/intersection and inside/on‐surface/outside relations, respectively. A theoretical framework is then formulated to compute the topological relations between any pair of elementary geometries using the two operators. A multidimensional, unified and geometry‐oriented algorithm is developed to compute topological relations between geometries. With this framework, the internal results of the topological relations computation are geometries. The topological relations can be illustrated with clear geometric meanings; at the same time, it can also be modified and updated parametrically. Case studies evaluating the topological relations between 3D objects are performed. The result suggests that our model can express and compute the topological relations between objects in a symbolic and geometry‐oriented way. The method can also support topological relation series computation between objects with location or shape changes.
    July 03, 2015   doi: 10.1111/tgis.12154   open full text
  • Student Learning in an Introductory GIS Course: Using a Project‐Based Approach.
    Forrest J. Bowlick, Sarah W. Bednarz, Daniel W. Goldberg.
    Transactions in GIS. July 03, 2015
    Introductory courses in Geographic Information Science (GIS) expose students to the concepts and practices necessary for future academic and professional use of GIS tools. Traditional GIS courses balance lectures in the theories of GIS with pre‐built and pre‐packaged lab activities to learn the practices of GIS. This article presents a case study of an experimental introductory course in which students conducted novel, independent project‐based group research under the supervision of graduate or advanced undergraduate students enrolled in the course, culminating in a class presentation and publication quality paper. Surveys and interviews indicated that students reacted more positively to project‐based group research than to traditional activities. Students felt the projects better prepared them for ‘real world’ applications of GIS, and recommend project‐based group research in other GIS coursework. Additionally, our findings indicate that students appreciate interactions with peers of varying skill levels and experiences, as these broaden their capabilities to work with other GIS users.
    July 03, 2015   doi: 10.1111/tgis.12146   open full text
  • Simulation of the Collection of Catch Crops for the Recovery of Agricultural Resources using Geographic and Statistical Data.
    Masayuki Matsuoka, Hideaki Nagare, Taku Fujiwara.
    Transactions in GIS. June 18, 2015
    The cultivation of catch crops has great potential in agricultural areas for the recovery of nutrients, mitigation of groundwater contamination, and secondary utilization of harvestry. To estimate the potential volume of catch crops that can be collected at prospective locations, we simulated the cultivation and collection process at a regional scale using geographic and statistical data. Three types of geographic data, namely the locations of greenhouses, collecting stations and road networks, were used in a geographic information system to compute the volume of collected catch crops and carrying distance between greenhouses and collecting stations. Carbon emission from transportation of the catch crop was calculated using an improved ton‐km method, and the results were compared with the carbon content of the catch crop to evaluate the carbon balance. We found that the total fresh weight of the collected catch crops was 67900 t, of which 70% was collected at the top 15 of 73 stations. Carbon emissions from transportation ranged from >1 to 12% of the carbon content of the catch crop. The analytical method used in this study can readily be applied to other environmental studies concerning the collection of agricultural products and other biomass resources.
    June 18, 2015   doi: 10.1111/tgis.12153   open full text
  • Evaluation and Monitoring of Service Quality: Discussing Ways to Meet INSPIRE Requirements.
    Christian Seip, Ralf Bill.
    Transactions in GIS. June 18, 2015
    Service oriented architectures (SOA) are widely used nowadays. As the name implies such architectures rely on services. Germany developed a marine‐specific service oriented data infrastructure (MDI‐DE – Marine Dateninfrastruktur Deutschland) from 2010 to 2013. The services in MDI‐DE can contribute to fulfilling reporting commitments for various European and national legislation. The services of MDI‐DE (just like other services affected, for instance, by INSPIRE) have to meet specific requirements regarding performance, availability and conformity (quality of service, QoS). Although SOA is an important field in scientific research there are very few publications and studies available on QoS, especially regarding INSPIRE requirements. The services of MDI‐DE were analyzed using various existing tools. Their usefulness to reflect where either the aspect's performance, availability or conformity needs improvement was partly verified. Due to varying results and the neglect of some services for various reasons it can be stated that the more tools are used, the more conclusive the outcome. Furthermore, service quality was not coherent when measured with different tools. This means that measuring QoS in terms of INSPIRE will be very difficult to do in the future and there is the danger that people will choose the tools with which their services perform best.
    June 18, 2015   doi: 10.1111/tgis.12145   open full text
  • Integrating the Huff Model and Floating Catchment Area Methods to Analyze Spatial Access to Healthcare Services.
    Jun Luo.
    Transactions in GIS. June 03, 2014
    Analysis of spatial access to healthcare services is critical for effective health resource planning. Gravity‐based spatial access models have been widely used to estimate spatial access to healthcare services. Among them, the floating catchment area (FCA) methods have been proved to be informative and helpful to the designation of Health Professional Shortage Areas (HPSAs). This article integrates the Huff Model with the FCA method to articulate population selection on services. Through the proposed approach, population demand on healthcare services is adjusted by a Huff Model‐based selection probability that reflects the impacts of both distance impedance and service site capacity. The new approach moderates the over‐ or under‐estimating of population demand that occurred with previous methods. Furthermore, the method uses a continuous distance impedance weight function instead of the arbitrarily defined subzones of previous studies. A case study of spatial access to primary care in Springfield, MO, showed that the proposed method can effectively moderate the population demand on service sites and therefore can generate more reliable spatial access measures.
    June 03, 2014   doi: 10.1111/tgis.12096   open full text
  • A Space‐Time Raster GIS Data Model for Spatiotemporal Analysis of Vegetation Responses to a Freeze Event.
    Ziliang Zhao, Shih‐Lung Shaw, Wang Dali.
    Transactions in GIS. May 27, 2014
    Many past space‐time GIS data models viewed the world mainly from a spatial perspective. They attached a time stamp to each state of an entity or the entire area of study. This approach is less efficient for certain spatio‐temporal analyses that focus on how locations change over time, which require researchers to view each location from a temporal perspective. In this article, we present a data model to organize multi‐temporal remote sensing datasets and track their changes at the individual pixel level. This data model can also integrate raster datasets from heterogeneous sources under a unified framework. The proposed data model consists of several object classes under a hierarchical structure. Each object class is associated with specific properties and behaviors to facilitate efficient spatio‐temporal analyses. We apply this data model to a case study of analyzing the impact of the 2007 freeze in Knoxville, Tennessee. The characteristics of different vegetation clusters before, during, and after the 2007 freeze event are compared. Our findings indicate that the majority of the study area is impacted by this freeze event, and different vegetation types show different response patterns to this freeze.
    May 27, 2014   doi: 10.1111/tgis.12088   open full text
  • Mapping Large Spatial Flow Data with Hierarchical Clustering.
    Xi Zhu, Diansheng Guo.
    Transactions in GIS. May 26, 2014
    It is challenging to map large spatial flow data due to the problem of occlusion and cluttered display, where hundreds of thousands of flows overlap and intersect each other. Existing flow mapping approaches often aggregate flows using predetermined high‐level geographic units (e.g. states) or bundling partial flow lines that are close in space, both of which cause a significant loss or distortion of information and may miss major patterns. In this research, we developed a flow clustering method that extracts clusters of similar flows to avoid the cluttering problem, reveal abstracted flow patterns, and meanwhile preserves data resolution as much as possible. Specifically, our method extends the traditional hierarchical clustering method to aggregate and map large flow data. The new method considers both origins and destinations in determining the similarity of two flows, which ensures that a flow cluster represents flows from similar origins to similar destinations and thus minimizes information loss during aggregation. With the spatial index and search algorithm, the new method is scalable to large flow data sets. As a hierarchical method, it generalizes flows to different hierarchical levels and has the potential to support multi‐resolution flow mapping. Different distance definitions can be incorporated to adapt to uneven spatial distribution of flows and detect flow clusters of different densities. To assess the quality and fidelity of flow clusters and flow maps, we carry out a case study to analyze a data set of 243,850 taxi trips within an urban area.
    May 26, 2014   doi: 10.1111/tgis.12100   open full text
  • Measuring the Reliability of Wheelchair User Route Planning based on Volunteered Geographic Information.
    Pascal Neis.
    Transactions in GIS. April 17, 2014
    The development of a wheelchair user friendly route planning application inherits a number of special requirements and details that need to be considered during the generation of the routing graph and the corresponding algorithm, making this task much more complex than car or pedestrian related applications. Each wheelchair type and, more importantly, each individual user might have different needs with regards to the way condition or other criteria. This study proposes a new approach to route planning for wheelchair users tailored for individual and personal requirements provided by the user and the calculation of a reliability factor of the computed wheelchair path. The routing graph is based on the freely available Volunteered Geographic Information (VGI) retrieved from the OpenStreetMap (OSM) project. The newly created algorithm is evaluated and tested for a selected area in Bonn, Germany. A new reliability factor is introduced that gives direct feedback about the quality of the generated path. Similar factor estimations can also be utilized for multiple route planning applications where VGI or other commercial or administrative data is implemented and more detailed factors than a simple geometric representation of a street network are of importance.
    April 17, 2014   doi: 10.1111/tgis.12087   open full text
  • Spatio‐Temporal Building Population Estimation for Highly Urbanized Areas Using GIS.
    Konstantin Greger.
    Transactions in GIS. April 17, 2014
    Detailed population information is crucial for the micro‐scale modeling and analysis of human behavior in urban areas. Since it is not available on the basis of individual persons, it has become necessary to derive data from aggregated census data. A variety of approaches have been published in the past, yet they are not entirely suitable for use in the micro‐scale context of highly urbanized areas, due mainly to their broad spatial scale and missing temporal scale. Here we introduce an enhanced approach for the spatio‐temporal estimation of building populations in highly urbanized areas. It builds upon other estimation methodologies, but extends them by introducing multiple usage categories and the temporal dimension. This allows for a more realistic representation of human activities in highly urbanized areas and the fact that populations change over time as a result of these activities. The model makes use of a variety of micro‐scale data sets to operationalize the activities and their spatio‐temporal representations. The outcome of the model provides estimated population figures for all buildings at each time step and thereby reveals spatio‐temporal behavior patterns. It can be used in a variety of applications concerning the implications of human behavior in urban areas.
    April 17, 2014   doi: 10.1111/tgis.12086   open full text
  • Integrating Spatial Data Linkage and Analysis Services in a Geoportal for China Urban Research.
    Xinyan Zhu, Bing She, Wei Guo, Shuming Bao, Di Chen.
    Transactions in GIS. April 01, 2014
    Many geoportals are now evolving into online analytical environments, where large amounts of data and various analysis methods are integrated. These spatiotemporal data are often distributed in different databases and exist in heterogeneous forms, even when they refer to the same geospatial entities. Besides, existing open standards lack sufficient expression of the attribute semantics. Client applications or other services thus have to deal with unrelated preprocessing tasks, such as data transformation and attribute annotation, leading to potential inconsistencies. Furthermore, to build informative interfaces that guide users to quickly understand the analysis methods, an analysis service needs to explicitly model the method parameters, which are often interrelated and have rich auxiliary information. This work presents the design of the spatial data linkage and analysis services in a geoportal for China urban research. The spatial data linkage service aggregates multisource heterogeneous data into linked layers with flexible attribute mapping, providing client applications and services with a unified access as if querying a big table. The spatial analysis service incorporates parameter hierarchy and grouping by extending the standard WPS service, and data‐dependent validation in computation components. This platform can help researchers efficiently explore and analyze spatiotemporal data online.
    April 01, 2014   doi: 10.1111/tgis.12084   open full text
  • An Iterative Detection and Removal Method for Detecting Spatial Clusters of Different Densities.
    Qiliang Liu, Jianbo Tang, Min Deng, Yan Shi.
    Transactions in GIS. March 24, 2014
    A fundamental element of exploratory spatial data analysis is the discovery of clusters in a spatial point dataset. When clusters with distinctly different local densities exist, the determination of suitable density level is still an unsolved problem. On that account, an iterative detection and removal method is proposed in this study. In each step of the novel method, there are two stages. In the detection stage, density level is statistically modeled as a significance level controlled by the number and support domain of the points in the dataset, and then a hypothesis test is used to detect the high‐density points. In the removal stage, the Delaunay triangulation network is used to construct clusters and support domains for the identified high‐density points, and then the high‐density points and their support domains are removed from the dataset. The detection and removal operation are iteratively implemented until no high‐density points can be detected. Experiments and comparisons show that the proposed method, on the one hand, outperforms four state‐of‐the‐art methods for detecting clusters of complex shapes and diverse densities, and on the other hand, no user‐specified parameters are required. In addition, the support domains of clusters are very useful for spatial analysis.
    March 24, 2014   doi: 10.1111/tgis.12083   open full text
  • Integrating a Raster Geographical Information System with Multi‐Objective Land Allocation Optimization for Conservation Reserve Design.
    WeiWei Dai, Samuel J. Ratick.
    Transactions in GIS. March 19, 2014
    The multi‐objective land allocation problem is to optimize the selection of land for different uses based on a set of decision objectives. For most applications, a geographical information system (GIS) is either absent or loosely coupled through file exchange. In this article the evolutionary algorithm (EA), a heuristic solution method for optimization problems, is integrated with a raster GIS to form a spatial decision support system (SDSS) for multi‐objective conservation reserve design. The SDSS effectively combines the functions of a GIS for data management, analysis, and visualization, with the optimization capability of the EA; and provides a uniform way to solve conservation reserve design problems with different types of constraints and objectives. The SDSS is demonstrated through application to the creation of conservation reserves in Bolivia to protect 17 endemic mammals.
    March 19, 2014   doi: 10.1111/tgis.12085   open full text
  • TimeBliography: A Dynamic and Online Bibliography on Temporal GIS.
    Willington Siabato, Christophe Claramunt, Miguel Ángel Manso‐Callejo, Miguel Ángel Bernabé‐Poveda.
    Transactions in GIS. March 05, 2014
    This article introduces an online bibliography on temporal GIS, a research area in which different scientific fields and researchers have provided substantial results and literature over the past few years. We first define the scientific domain of temporal GIS, its origin and recent evolution, and the context of this bibliography. Then, the components and functionalities of the web‐based application that support the online bibliography are described. The bibliography, entitled TimeBliography, is accessible on the Web at
    March 05, 2014   doi: 10.1111/tgis.12080   open full text
  • Experimental Analysis of Various Types of Road Intersections for Interchange Detection.
    Qi Zhou, Zhilin Li.
    Transactions in GIS. February 28, 2014
    Road interchanges are a major pattern type in road networks. Recognition of road interchanges benefits automated road network generalization, car navigation and traffic flow analysis. This study first investigated several existing approaches to automatically detecting interchanges in a road network, and determined that the recognition of characteristic road intersections is essential for the effective detection of interchanges. Several experiments were carried out to investigate nine types of road intersections for interchange detection and to analyze characteristic ones. Furthermore, an approach to the detection of both intersections and segments of interchanges was proposed and validated. The road networks across different scales were tested and results show that: (1) the T‐shaped and Cross‐shaped junctions are very common in road networks, but they are not the most characteristic ones for interchange detection; (2) the y‐shaped, Y‐shaped types, X‐shaped, Fork‐shaped and Multi‐leg may be the characteristic types for interchange detection; (3) the proposed approach to detecting interchanges is effective, and most of the intersections and segments of interchanges can be detected. In addition, taking multiple characteristic types into consideration for interchange detection is suggested.
    February 28, 2014   doi: 10.1111/tgis.12077   open full text
  • Employing Internet GIS Surveys to Characterize Recreational Boating Travel Patterns.
    Yue Cui, Edward Mahoney.
    Transactions in GIS. February 28, 2014
    Spatial factors are fundamental features of the tourism and recreation phenomenon. In terms of recreational boating, scholars are interested both in boaters' spatial distribution and movement patterns and in the factors associated with their movements, e.g. travel costs, environmental impacts, and social impacts of the movements. Spatial factors are also key to policymakers' decisions about where to establish new boating facilities, how protected areas are used by boaters and in crafting policy that minimizes conflict between recreational boating and other waterway uses. However, systematic studies regarding the recreationist movement are scant, especially at the fine geographic level. One reason for the lack of research is that gathering spatial data presents significant practical problems. In the Florida Saltwater Fishing Study, we integrated Google Map APIs into the online survey instrument to collect spatially‐referenced data regarding boaters' movement on water. Results appear to be accurate, highly cost effective, and easily integrated with other survey information such as angler catch, effort, expenditures and attitudes.
    February 28, 2014   doi: 10.1111/tgis.12079   open full text
  • Noisy Data Smoothing in DEM Construction Using Least Squares Support Vector Machines.
    Chuanfa Chen, Yanyan Li, Honglei Dai, Xuewei Cao.
    Transactions in GIS. February 26, 2014
    Since spatial datasets are subject to sampling errors, a smoothing interpolation method should be employed to remove noise during DEM construction. Although least squares support vector machines (LSSVM) have been widely accepted as a classifier, their effect on smoothing noisy data is almost unknown. In this article, the smoothness of LSSVM was explored, and its effect on smoothing noisy data in DEM construction was tested. In order to improve the ability to deal with large datasets, a local method of LSSVM has been developed, where only the neighboring sampling points around the one to be estimated are used for computation. A numerical test indicated that LSSVM is more accurate than the classical smoothing methods including TPS and kriging, and its error surfaces are more evenly distributed. The real‐world example of smoothing noise inherent in lidar‐derived DEMs also showed that LSSVM has a positive smoothing effect, which is approximately as accurate as TPS. In short, LSSVM with a high efficiency can be considered as an alternative smoothing method for smoothing noisy data in DEM construction.
    February 26, 2014   doi: 10.1111/tgis.12078   open full text
  • Detecting and Analyzing Mobility Hotspots using Surface Networks.
    Yujie Hu, Harvey J. Miller, Xiang Li.
    Transactions in GIS. February 17, 2014
    Capabilities for collecting and storing data on mobile objects have increased dramatically over the past few decades. A persistent difficulty is summarizing large collections of mobile objects. This article develops methods for extracting and analyzing hotspots or locations with relatively high levels of mobility activity. We use kernel density estimation (KDE) to convert a large collection of mobile objects into a smooth, continuous surface. We then develop a topological algorithm to extract critical geometric features of the surface; these include critical points (peaks, pits and passes) and critical lines (ridgelines and course‐lines). We connect the peaks and corresponding ridgelines to produce a surface network that summarizes the topological structure of the surface. We apply graph theoretic indices to analytically characterize the surface and its changes over time. To illustrate our approach, we apply the techniques to taxi cab data collected in Shanghai, China. We find increases in the complexity of the hotspot spatial distribution during normal activity hours in the late morning, afternoon and evening and a spike in the connectivity of the hotspot spatial distribution in the morning as taxis concentrate on servicing travel to work. These results match with scientific and anecdotal knowledge about human activity patterns in the study area.
    February 17, 2014   doi: 10.1111/tgis.12076   open full text
  • Exploring and Visualizing Differences in Geographic and Linguistic Web Coverage.
    Ramya Venkateswaran, Robert Weibel, Ross S. Purves.
    Transactions in GIS. January 27, 2014
    This article reports on a study performed to understand the geographic and linguistic coverage of web resources, focusing on the example of tourism‐related themes in Switzerland. Search engine queries of web documents were used to gather counts for phrases in four different languages. The study focused on selected populated places and tourist attractions in Switzerland from three gazetteer datasets: topographic gazetteer data from the Swiss national mapping agency (SwissTopo); POI data from a commercial data provider (Tele Atlas) and user generated geographic content ( The web counts illustrate the geographic extent and trends of web coverage of tourism for different languages. Results show that coverage for local languages, i.e. German, French and Italian, is more strongly related to the region of the spoken language. Correlation of the web counts to typical tourism indicators, e.g. population and number of hotel nights rented per year, are also computed and compared.
    January 27, 2014   doi: 10.1111/tgis.12071   open full text
  • Mining Trajectory Data and Geotagged Data in Social Media for Road Map Inference.
    Jun Li, Qiming Qin, Jiawei Han, Lu‐An Tang, Kin Hou Lei.
    Transactions in GIS. January 15, 2014
    As mapping is costly and labor‐intensive work, government mapping agencies are less and less willing to absorb these costs. In order to reduce the updating cycle and cost, researchers have started to use user generated content (UGC) for updating road maps; however, the existing methods either rely heavily on manual labor or cannot extract enough information for road maps. In view of the above problems, this article proposes a UGC‐based automatic road map inference method. In this method, data mining techniques and natural language processing tools are applied to trajectory data and geotagged data in social media to extract not only spatial information – the location of the road network – but also attribute information – road class and road name – in an effort to create a complete road map. A case study using floating car data, collected by the National Commercial Vehicle Monitoring Platform of China, and geotagged text data from Flickr and Google Maps/Earth, validates the effectiveness of this method in inferring road maps.
    January 15, 2014   doi: 10.1111/tgis.12072   open full text
  • A Comprehensive Framework for Intrinsic OpenStreetMap Quality Analysis.
    Christopher Barron, Pascal Neis, Alexander Zipf.
    Transactions in GIS. December 23, 2013
    OpenStreetMap (OSM) is one of the most popular examples of a Volunteered Geographic Information (VGI) project. In the past years it has become a serious alternative source for geodata. Since the quality of OSM data can vary strongly, different aspects have been investigated in several scientific studies. In most cases the data is compared with commercial or administrative datasets which, however, are not always accessible due to the lack of availability, contradictory licensing restrictions or high procurement costs. In this investigation a framework containing more than 25 methods and indicators is presented, allowing OSM quality assessments based solely on the data's history. Without the usage of a reference data set, approximate statements on OSM data quality are possible. For this purpose existing methods are taken up, developed further, and integrated into an extensible open source framework. This enables arbitrarily repeatable intrinsic OSM quality analyses for any part of the world.
    December 23, 2013   doi: 10.1111/tgis.12073   open full text
  • Information Rich GIS Dissemination in Disconnected Environments.
    William Johnston, Nilanjan Banerjee, Jackson Cothren, James P. Parkerson.
    Transactions in GIS. December 02, 2013
    Information‐rich maps are today rendered from powerful back‐end servers. Unfortunately, there may be circumstances in which access to such Internet‐resident web services is infeasible or unreliable. These disconnected environments can theoretically occur during major power outages, malicious attacks on communications infrastructure, natural disasters, or in remote operating environments. One might also envision applications in which a disconnected service is preferred over Internet‐resident services, such as when the local internet service is overloaded with traffic, making communication though it difficult. To this end, this article presents a software stack (a map stack) that can serve GIS information from low power embedded nodes. The system combines a spatially enabled SQL database, location‐based routing, and multi‐scale map rendering to serve information‐rich GIS data on common hand‐held devices at minimal energy consumption. The maps are rendered on browsers on off‐the‐shelf mobile devices such as smart phones and tablets. The system also provides a crowd sourced capability where end users can annotate maps with up‐to‐date information on the scene of the natural disaster. We have prototyped a fully functional map stack on a battery powered Gumstix Overo air platform. We show that the map stack is a highly extensible platform that provides low latency, and low energy dissemination of maps during a natural disaster.
    December 02, 2013   doi: 10.1111/tgis.12053   open full text
  • Semantically Enriching an Open Source Sensor Observation Service Implementation for Accessing Heterogeneous Environmental Data Sources.
    Désirée Hilbring, Anastasia Moumtzidou, Jürgen Moßgraber, Stefanos Vrochidis.
    Transactions in GIS. December 02, 2013
    Many kinds of environmental data are nowadays publicly available, but spread over the web. This article discusses using the Sensor Observation Service (SOS) standard of the Open Geospatial Consortium (OGC) as a common interface for providing data from heterogeneous sources which can be integrated to a user tailored environmental information system. In order to allow for providing user‐tailored and problem‐specific information the adjusted SOS is augmented by a semantic layer which maps the environmental information to ontology concepts. The necessary information fusion from different domains and data types lead to several specific requirements for the SOS. Addressing these requirements we have implemented a SOS which still conforms to the OGC SOS 1.0.0 standard specification. The developed SOS has been integrated in a publicly available demonstrator of our personalized environmental information system. Additionally this article discusses future consequences for the SOS, caused by the recently published SOS 2.0 specification.
    December 02, 2013   doi: 10.1111/tgis.12055   open full text
  • A New Framework for Solving the Spatial Network Problems Based on Line Graphs.
    Javad Saberian, Mohammad Reza Malek, Stephan Winter, Majid Hamrah.
    Transactions in GIS. December 02, 2013
    In this article we define inverse line graphs of directed graphs as a new framework for solving some classical network analysis problems. The extraction method and theories of inverse line graphs are explained in this article. It is shown that by changing the analysis space from the original directed graph to the inverse line graph, complex problems can be changed into simpler problems. We show the usefulness of the proposed framework in two particular applications: shortest path computations and the more general route planning. Considering the implementation result, we expect that this framework could be used in many more network analysis problems.
    December 02, 2013   doi: 10.1111/tgis.12064   open full text
  • Modeling Use of Space from Social Media Data Using a Biased Random Walker.
    Steven D. Prager, R. Paul Wiegand.
    Transactions in GIS. November 18, 2013
    Individuals and other entities move through space as a function of local characteristics of place, their internal behavioral models, and the topological structure of the underlying space. When a collection of locations (i.e. geotagged photos or other geotagged social media information) from a large number of individuals is assembled, it becomes possible to understand the interrelationship between the individuals and the space they occupy. This research systematically considers this interrelationship through an examination of the effect of the intersection of behavioral and spatial characteristics on individuals moving on street networks. The research illustrates how social media data, in combination with a biased random walker, can be used to understand and model the interaction of spatial structure and social‐environmental factors on influencing individuals' use of their environment. The biased walker offers a flexible approach to incorporate consideration of both social‐environmental and structural factors into a model and we demonstrate this through a case study wherein we are able to use the random walker to model the characteristics of Flickr users in New York City.
    November 18, 2013   doi: 10.1111/tgis.12069   open full text
  • Collaborative Ontology Development for the Geosciences.
    Reza Kalbasi, Krzysztof Janowicz, Femke Reitsma, Luc Boerboom, Ali Alesheikh.
    Transactions in GIS. November 11, 2013
    Ontology‐based information publishing, retrieval, reuse, and integration have become popular research topics to address the challenges involved in exchanging data between heterogeneous sources. However, in most cases ontologies are still developed in a centralized top‐down manner by a few knowledge engineers. Consequently, the role that developers play in conceptualizing a domain such as the geosciences is disproportional compared with the role of domain experts and especially potential end‐users. These and other drawbacks have stimulated the creation of new methodologies focusing around collaboration. Based on a review of existing approaches, this article presents a two‐step methodology and implementation to foster collaborative ontology engineering in the geosciences. Our approach consists of the development of a minimalistic core ontology acting as a catalyst and the creation of a virtual collaborative development cycle. Both methodology and prototypical implementation have been tested in the context of the EU‐funded ForeStClim project which addresses environmental protection with respect to forests and climate change.
    November 11, 2013   doi: 10.1111/tgis.12070   open full text
  • Temporal Accuracy in Urban Growth Forecasting: A Study Using the SLEUTH Model.
    Gargi Chaudhuri, Keith C. Clarke.
    Transactions in GIS. September 12, 2013
    This study attempts to establish multi‐temporal accuracy of the predicted maps produced by a land use change simulation model over time. Validation of the forecasted results is an essential part of predictive modeling and it becomes even more important when the models are used for decision making purposes. The present study uses a popular land use change model called SLEUTH to investigate the temporal trend of accuracy of the predicted maps. The study first investigates the trend of accuracy of the predicted maps from the immediate future to the distant future. Secondly, it investigates the impact of the prediction date range on the accuracy of the predicted maps. The objectives are tested for the city of Gorizia (Italy) using three sets of map comparison techniques, Kappa coefficients, Kappa Simulation and quantity disagreement and allocation disagreement. Results show that, in addition to the model's performance, the decrease in the accuracy of the predicted maps is dependent on factors such as urban history, uncertainty of input data and accuracy of reference maps.
    September 12, 2013   doi: 10.1111/tgis.12047   open full text
  • On the Importance of Time for GIS View Measures and Their Use in Hedonic Property Models: Does Being Temporally Explicit Matter?
    Thomas W. Crawford, Okmyung Bin, Jamie B. Kruse, Craig E. Landry.
    Transactions in GIS. August 16, 2013
    Progress in GIScience has advanced the ability to represent and analyze view characteristics. GIS‐derived view measures requiring digital elevation surface models are used in hedonic property models to quantify the amenity value of view for parcel sales transactions. Ideally models should represent surface elevations that are temporally synchronized with parcel sale dates. Temporal synchronization for studies spanning multiple years may require significant effort. Few studies have undertaken this effort, leading us to investigate in this research the need to be temporally explicit. We evaluate two competing surface model approaches based on: (1) a single year 2000 LiDAR surface product; and (2) annual‐specific surface products for 1995–2002. Two competing view measures based on the different surface approaches are constructed for 561 parcel transactions during 1995–2002 in a coastal North Carolina county and are input into hedonic regression models. Results showed that being temporally explicit did matter in terms of finding significantly different view measures but did not matter in terms of finding significantly different effects of view on parcel sales prices. Despite mixed results for our case study, we advise that future research involving GIS‐based view measurement should consider the spatial and temporal contexts of study area development patterns when evaluating the need to be temporally explicit.
    August 16, 2013   doi: 10.1111/tgis.12036   open full text
  • Knowledge and Reasoning in Spatial Analysis.
    Andreas Hall, Paula Ahonen‐Rainio, Kirsi Virrantaus.
    Transactions in GIS. August 14, 2013
    Reasoning is an essential part of any analysis process. Especially in visual analytics, the quality of the results depends heavily on the knowledge and reasoning skills of the analyst. In this study, we consider how to make the results transparent by visualizing the reasoning and the knowledge, so that persons from outside can trace and verify them. The focus of this study is in spatial analysis and a case study was carried out on a process of off‐road mobility analysis. In the case study, linked views of a map and a PCP were identified as reasoning artifacts. The knowledge used by the analyst was formed by these artifacts and the tangible pieces of information identified in them, along with the mental models of the analyst′s mind. To make the results transparent, the tangible pieces of information were marked with sketches and the mental models were presented in causal graphs because it was found that causality was central to the reasoning process in the case study. The causal graph allows the reasoning of the analyst to be studied, as well as traced back to its origin.
    August 14, 2013   doi: 10.1111/tgis.12049   open full text
  • Linking Time Geography and Activity Theory to Support the Activities of Mobile Information Seekers.
    Paul Crease, Tumasch Reichenbacher.
    Transactions in GIS. August 02, 2013
    Mobile geographic information seeking systems are often employed to support spatial activities in an unfamiliar geographic environment. However, current systems are unable to incorporate the spatio‐temporal constraints of these activities in order to support this information seeking. This article describes a methodology addressing the nature of these spatio‐temporal activities that has the potential to contribute solutions to this problem. A key element of this approach is the awareness that both the planning and acting phases must be considered in supporting such activities. This means the development of plans that can be amended ad‐hoc, whilst still adhering to the spatio‐temporal constraints of the activity. The results of such an approach are the ability for a more descriptive representation of a spatio‐temporal activity, which can then be used to support spatio‐temporal accessibility analyses and disclose geographic information objects that are no longer accessible to the mobile information seeker. The introduction of these spatio‐temporal constraints also allows the mobile information seeker to build up an itinerary that adheres to the given spatio‐temporal constraints of the activity.
    August 02, 2013   doi: 10.1111/tgis.12044   open full text
  • GIS Course Planning: A Comparison of Syllabi at US College and Universities.
    Thomas A. Wikle, Todd D. Fagin.
    Transactions in GIS. June 21, 2013
    Despite the enormous growth of college courses dealing with spatial information, curriculum planning involving geographic information science (GIS) courses and programs has received little attention within the GIS literature. As the number and variety of GIS courses expands, so too does the importance of both systematic and inclusive planning and campus‐wide coordination. In this article we explore course planning through an exploration of 312 GIS course syllabi used at US colleges and universities with the goal of characterizing the degree to which learning resources, student evaluation methods, and course topics have become standardized across institution types, academic levels, and disciplines. Our findings reveal a consensus in the use of GIS software across courses but no similar agreement in the use of textbooks. Hands‐on activities were used as evaluation methods in nearly every course in the sample regardless of institution type or academic level. However, quizzes, tests and final exams were used more often in community colleges while papers and projects were used more frequently in four‐year and comprehensive research universities. The frequency of topic categories listed on syllabi was relatively consistent across institutions, academic levels and disciplines with a few topics such as vector analytic operations, data models, and data creation/acquisition/editing included on more than 50% of syllabi.
    June 21, 2013   doi: 10.1111/tgis.12048   open full text
  • A Temporal Variant‐Invariant Validation Approach for Agent‐based Models of Landscape Dynamics.
    Christopher Bone, Bart Johnson, Max Nielsen‐Pincus, Eric Sproles, John Bolte.
    Transactions in GIS. June 09, 2013
    Agent‐based modeling provides a means for addressing the way human and natural systems interact to change landscapes over time. Until recently, evaluation of simulation models has focused on map comparison techniques that evaluate the degree to which predictions match real‐world observations. However, methods that change the focus of evaluation from patterns to processes have begun to surface; that is, rather than asking if a model simulates a correct pattern, models are evaluated on their ability to simulate a process of interest. We build on an existing agent‐based modeling validation method in order to present a temporal variant‐invariant analysis (TVIA). The enhanced method, which focuses on analyzing the uncertainty in simulation results, examines the degree to which outcomes from multiple model runs match some reference to how land use parcels make the transition from one land use class to another over time. We apply TVIA to results from an agent‐based model that simulates the relationships between landowner decisions and wildfire risk in the wildland‐urban interface of the southern Willamette Valley, Oregon, USA. The TVIA approach demonstrates a novel ability to examine uncertainty across time to provide an understanding of how the model emulates the system of interest.
    June 09, 2013   doi: 10.1111/tgis.12016   open full text
  • A Comparative Analysis of Traveling Salesman Solutions from Geographic Information Systems.
    Kevin M. Curtin, Gabriela Voicu, Matthew T. Rice, Anthony Stefanidis.
    Transactions in GIS. June 09, 2013
    The Traveling Salesman Problem is one of the most prominent problems in combinatorial optimization, and is regularly employed in a wide variety of applications. The objective of this article is to demonstrate the extent of sub‐optimality produced by Traveling Salesman solution procedures implemented in the context of Geographic Information Systems and to discuss the consequences that such solutions have for practice. Toward that end, an analysis is made of Traveling Salesman solutions from implementations in four Geographic Information System packages. These implementations are tested against the optimal solution for a range of problem sizes. Computational results are presented in the context of a school bus routing application. This analysis concludes that no Traveling Salesman implementation in GIS is likely to find the optimal solution when problems exceed 10 stops. In contrast, optimal solutions can be generated with desktop linear programming software for up to 25 cities. Moreover, one GIS implementation consistently found solutions that were closer to optimal than its competitors. This research strongly suggests that for applications with fewer than 25 stops, the use of an optimal solution procedure is advised, and that GIS implementations can benefit from the integration of more robust optimization techniques.
    June 09, 2013   doi: 10.1111/tgis.12045   open full text
  • Assessing the Veracity of Methods for Extracting Place Semantics from Flickr Tags.
    William A Mackaness, Omair Chaudhry.
    Transactions in GIS. May 28, 2013
    The volume and potential value of user generated content (UGC) is ever growing. Multiply sourced, its value is greatly increased by the inclusion of metadata that adequately and accurately describes that content – particularly if such data are to be integrated with more formal data sets. Typically, digital photography is tagged with location and attribute information that variously describe the location, events or objects in the image. Often inconsistent and incomplete, these attributes reflect concepts at a range of geographic scales. From a spatial data integration perspective, the information relating to “place” is of primary interest. The challenge therefore is in selecting the most appropriate tags that best describe the geography of the image. This article presents a methodology based on an information retrieval technique that separates out “place related tags” from the remainder of the tags. Different scales of geography are identified by varying the size of the sampling area within which the imagery falls. This is applied in the context of urban environments, using Flickr imagery. Empirical analysis is then used to assess the correctness of the chosen tags (i.e. whether the tag correctly describes the geographic region in which the image was taken). Logistic regression and Bayesian inference are used to attach a probability value to each place tag. The high correlation values achieved indicate that this methodology can be used to automatically select place tags for any urban region and thus hierarchically structure UGC in order that it can be semantically integrated with other data sources.
    May 28, 2013   doi: 10.1111/tgis.12043   open full text
  • Temporal Uncertainty in a Small Area Open Geodemographic Classification.
    Christopher G. Gale, Paul A. Longley.
    Transactions in GIS. May 22, 2013
    The 2001 Output Area Classification (2001 OAC) is an open source geodemographic classification of the UK built exclusively from 2001 UK Census data. There has been considerable user interest in its applicability to subsequent time periods, particularly given the potential propensity of characteristics and attributes in some areas to change during inter‐censual periods. Users often purchase commercial geodemographic classification products in the belief that purely census‐based classifications such as the 2001 OAC are uniformly unreliable because there is no temporal updating of input data. Yet there is evidence to suggest that whilst some UK neighborhoods are prone to sudden changes, many others change very little over protracted time periods. Using measures that are available at the small area level, temporal uncertainty indicators can be constructed to identify those areas that are less stable. Using mid‐year population estimates and dwelling stock data, this article develops three temporal uncertainty indicators. These provide a reliable means of gauging the stability or otherwise of neighborhood conditions. The conclusion from this is that while a large number of small areas in the UK do experience change over time, this change is not uniform in either degree or distribution, or by geodemographic type.
    May 22, 2013   doi: 10.1111/tgis.12035   open full text
  • How Reliable are Citizen‐Derived Scientific Data? Assessing the Quality of Contrail Observations Made by the General Public.
    Amy Fowler, J. Duncan Whyatt, Gemma Davies, Rebecca Ellis.
    Transactions in GIS. May 22, 2013
    Citizen science projects encourage the general public to participate in scientific research. Participants can contribute large volumes of data over broad spatial and temporal frames; however, the challenge is to generate data of sufficient quality to be useable in scientific research. Most observations made by citizen‐scientists can be independently verified by “experts”. However, verification is more problematic when the phenomena being recorded are short‐lived. This article uses a GIS methodology to verify the quality of contrail observations made by the general public as part of the OPAL Climate Survey. We verify observations using datasets derived from a variety of different sources (experts, models and amateur enthusiasts) with different spatial and temporal properties which reflect the complex 3D nature of the atmosphere. Our results suggest that ∼70% of citizen observations are plausible, based on favorable atmospheric conditions and the presence or absence of aircraft; a finding which is in keeping with other, more conventional citizen science projects. However, questions remain as to why the quality of the citizen‐based observations was so high. Given the lack of supporting data on observers, it is impossible to determine whether the dataset was generated by the activities of many participants or a small but dedicated number of individual observers.
    May 22, 2013   doi: 10.1111/tgis.12034   open full text
  • UML‐Based Approach to Developing a CityGML Application Domain Extension.
    Linda Brink, Jantien Stoter, Sisi Zlatanova.
    Transactions in GIS. May 22, 2013
    Recently a national 3D standard was established in the Netherlands as a CityGML Application Domain Extension (called IMGeo). In line with the Dutch practice of modeling geo‐information, the ADE is developed using a model driven approach. The classes are designed in UML and automatically mapped to GML schema. The current OGC CityGML specification does not provide rules or guidance on correctly modeling an ADE in UML. This article fills this gap by studying how CityGML can be extended for specific applications starting from the UML diagrams. Six alternatives for modeling ADEs in UML are introduced and compared. The optimal alternative is selected and applied to obtain the national 3D standard. The approach was extensively discussed with international experts, who were members of both SIG3D and other working groups. As a consequence the approach was adopted by the SIG3D, the Special Interest Group 3D which, among other things, work on the 3D standard CityGML in cooperation with OGC. Therefore the approach contains many issues that can be generalized and reused by future domain extensions of CityGML. To further support this, the article formulates a model‐driven framework to model CityGML ADEs. Open issues are described in the conclusions.
    May 22, 2013   doi: 10.1111/tgis.12026   open full text
  • Combining the Arc Marine Framework with Geographic Metadata to Support Ocean Acoustic Modeling.
    Anthony W. Isenor, Tobias W. Spears.
    Transactions in GIS. May 22, 2013
    A data model for use in a rapid environmental assessment system is constructed. The data model is used in an information layer that supports acoustic assessments of the ocean environment. Such an assessment requires use of both historic and real‐time oceanographic data. The foundation of the data model is Arc Marine, a framework specification for geospatial oceanographic databases that provides structures for containing the basic data types used in oceanographic research. Arc Marine also allows design extensions to account for application specific data structures as demonstrated through incorporation of aspects of the International Organization for Standardization (ISO) 19115 Geographic Information–Metadata standard. The ISO 19115 standard provides structures for recording the historic processing of the data sets. The data model is used to construct a database in the open source database management system (DBMS) PostgreSQL. The resulting system also incorporates the concept of user exits, the seamless extension of the DBMS through inclusion of application‐specific software.
    May 22, 2013   doi: 10.1111/tgis.12029   open full text
  • An Algebra for Spatiotemporal Data: From Observations to Events.
    Karine Reis Ferreira, Gilberto Camara, Antônio Miguel Vieira Monteiro.
    Transactions in GIS. May 22, 2013
    Recent technological advances in geospatial data gathering have created massive data sets with better spatial and temporal resolution than ever before. These large spatiotemporal data sets have motivated a challenge for Geoinformatics: how to model changes and design good quality software. Many existing spatiotemporal data models represent how objects and fields evolve over time. However, to properly capture changes, it is also necessary to describe events. As a contribution to this research, this article presents an algebra for spatiotemporal data. Algebras give formal specifications at a high‐level abstraction, independently of programming languages. This helps to develop reliable and expressive applications. Our algebra specifies three data types as generic abstractions built on real‐world observations: time series, trajectory and coverage. Based on these abstractions, it defines object and event types. The proposed data types and functions can model and capture changes in a large range of applications, including location‐based services, environmental monitoring, public health, and natural disasters.
    May 22, 2013   doi: 10.1111/tgis.12030   open full text
  • Assessing the Accuracy of Volunteered Geographic Information arising from Multiple Contributors to an Internet Based Collaborative Project.
    G. M. Foody, L. See, S. Fritz, M. Van der Velde, C. Perger, C. Schill, D. S. Boyd.
    Transactions in GIS. May 22, 2013
    The recent rise of neogeography and citizen sensing has increased the opportunities for the use of crowdsourcing as a means to acquire data to support geographical research. The value of the resulting volunteered geographic information is, however, often limited by concerns associated with its quality and the degree to which the contributing data sources may be trusted. Here, information on the quality of sources of volunteered geographic information was derived using a latent class analysis. The volunteered information was on land cover interpreted visually from satellite sensor images and the main focus was on the labeling of 299 sites by seven of the 65 volunteers who contributed to an Internet‐based collaborative project. Using the information on land cover acquired by the multiple volunteers it was shown that the relative, but not absolute, quality of the data from different volunteers could be characterized accurately. Additionally, class‐specific variations in the quality of the information provided by a single volunteer could be characterized by the analysis. The latent class analysis, therefore, was able to provide information on the quality of information provided on an inter‐ and intra‐volunteer basis.
    May 22, 2013   doi: 10.1111/tgis.12033   open full text
  • Airborne LiDAR and Terrestrial Laser Scanning Derived Vegetation Obstruction Factors for Visibility Models.
    Jayson Murgoitio, Rupesh Shrestha, Nancy Glenn, Lucas Spaete.
    Transactions in GIS. May 17, 2013
    Research presented here explores the feasibility of leveraging vegetation data derived from airborne light detection and ranging (LiDAR) and terrestrial laser scanning (TLS) for visibility modeling. Using LiDAR and TLS datasets of a lodgepole pine (Pinus contorta) dominant ecosystem, tree canopy and trunk obstructions were isolated relevant to a discrete visibility beam in a short‐range line‐of‐sight model. Cumulative obstruction factors from vegetation were compared with reference visibility values from digital photographs along sightline paths. LiDAR‐derived tree factors were augmented with single‐scan TLS data for obstruction prediction. Good correlation between datasets was found up to 10 m from the terrestrial scanner, but fine scale visibility modeling was problematic at longer distances. Analysis of correlation and regression results reveal the influence of obstruction shadowing inherent to discrete LiDAR and TLS, potentially limiting the feasibility of modeling visibility over large areas with similar technology. However, the results support the potential for TLS‐derived subcanopy metrics for augmenting large amounts of aerial LiDAR data to significantly improve models of forest structure. Subtle LiDAR processing improvements, including more accurate tree delineation through higher point density aerial data, combined with better vegetation quantification processes for TLS data, will advance the feasibility and accuracy of data integration.
    May 17, 2013   doi: 10.1111/tgis.12022   open full text
  • A Morphological Approach to Predicting Urban Expansion.
    Jamal Jokar Arsanjani, Marco Helbich, Ali Jafar Mousivand.
    Transactions in GIS. May 17, 2013
    Many methods for modeling urban expansion are available. Most of these computational models demand a variety of large‐scale environmental and socio‐economic data to investigate the relationship between urban expansion and its driving forces. These requirements are not always fulfilled, particularly in developing countries due to a lack of data availability. This necessitates methods not suffering from data limitations to ease their application. Consequently, this research presents a morphological approach for predicting urban expansion on the basis of spatiotemporal dynamics of urban margins by investigating the interior metropolitan area of Tehran, Iran as a case study. To assess the model's performance, urban expansion is monitored from 1976 to 2012. The proposed model is evaluated to ensure that the prediction performance for the year 2012 is acceptable. For the year 2024, the model predicts Tehran's urban expansion at an overall R2 of 88%. Accordingly, it is concluded that: (1) although this approach only inputs urban margins, it represents a suitable and easy‐to‐use urban expansion model; and (2) urban planners are faced with continuing urban expansion.
    May 17, 2013   doi: 10.1111/tgis.12031   open full text
  • Appreciative GIS and Strength‐Based Community Change.
    Paddington Hodza.
    Transactions in GIS. May 17, 2013
    Problem‐solving is embedded deeply in the digital DNA of GIS. Most projects involving GIS 1.0 and 2.0 raise community weaknesses, failures and other problems and use them to motivate change. The projects often create a future that does not differ greatly from the past or last long. Although looking into community problems is important and sometimes necessary, the steps of problem‐solving do not always leave people feeling happy. To inspire communities to create change based on their strengths and achievements, and to provide better participant experience, this article develops the concept of a new form of GIS called Appreciative GIS (AGIS). AGIS are grounded in the affirmative premise that every community, however challenged, is gifted with certain assets, potentials and strengths which, when effectively exploited, can take that community to a better and sustainable future. Based on Earth's internal structure, the article develops a useful layered community model where crust, mantle and core strata represent the community's body, life‐draining and life‐giving elements in that order. The model helps explain the different views of the community from current GIS and AGIS perspectives. A Total GIS (TGIS) cube is also developed and used to indicate that current GIS commonly focus on elements of the mantle or what we do not have, what we cannot do and what makes us weak. AGIS, on the other hand, dig up the core and cultivate what we have, what we can possibly do and what makes us strong. In a significant departure from the linear approach of problem‐solving, the article suggests implementing AGIS through a 7G cyclical method. The article contends that although AGIS may not be the whole enchilada, they can serve as a beacon of hope and a powerful source of inspiration especially for individuals and groups who are perceived or made to perceive themselves as dysfunctional, weak or poor.
    May 17, 2013   doi: 10.1111/tgis.12046   open full text
  • Thinking about Space‐Time Connections: Spatiotemporal Scheduling of Individual Activities.
    Kathleen Stewart, Junchuan Fan, Emily White.
    Transactions in GIS. May 17, 2013
    This article presents a spatiotemporal model for scheduling applications that is driven by the events and activities individuals plan and manage every day. The framework is presented using an ontological approach where ontologies at different levels of generalization, e.g. domain, application, and task ontologies, are linked together through participation and inheritance relationships. S_Events are entered into a schedule as a new S_Entry, or modifications can be made to existing entries including reschedule, postpone, change location, and delete as schedules vary over time. These schedule updates are formalized through changes to planned start and end times and the planned locations of S_Entries are expressed using SWRL, a semantic web rule language. SWRL is also used for reasoning about schedule changes and the space‐time conflicts that can occur. The sequence of entries in a schedule gives rise to S_trajectories representing the locations that individuals plan to visit in order to carry out their schedule, adding an additional spatial element to the framework. A prototype Geoscheduler application maps S_Entries against a timeline, offering a spatiotemporal visualization of scheduled activities showing the evolution of a schedule over space‐time and affecting spatiotemporal accessibility for individuals.
    May 17, 2013   doi: 10.1111/tgis.12028   open full text
  • Estimating the Vehicle‐Miles‐Traveled Implications of Alternative Metropolitan Growth Scenarios: A Boston Example.
    Joseph Ferreira, Mi Diao, Jingsi Xu.
    Transactions in GIS. May 09, 2013
    This study demonstrates the potential value, and difficulties, in utilizing large‐scale, location aware, administrative data together with urban modeling to address current policy issues in a timely fashion. We take advantage of a unique dataset of millions of odometer readings from annual safety inspections of all private passenger vehicles in Metropolitan Boston to estimate the vehicle‐miles‐traveled (VMT) implication of alternative metropolitan growth scenarios: a sprawl‐type “let‐it‐be” scenario and a smart‐growth‐type “winds‐of‐change” scenario. The data are georeferenced to 250 × 250 m grid cells developed by MassGIS. We apply a greedy algorithm to assign Traffic Analysis Zone (TAZ) level household growth projections to grid cells and then use spatial interpolation tools to estimate VMT‐per‐vehicle surfaces for the region. If new growth households have similar VMT behavior as their neighbors, then the let‐it‐be scenario will generate 12–15% more VMT per household compared to the winds‐of‐change scenario. However, even the “wind‐of‐change” scenario, will result in new households averaging higher VMT per household than the Metro Boston average observed in 2005. The implication is that urban growth management can significantly reduce GHG but, by itself, will not be sufficient to achieve the GHG emission reduction targets set by the State for the transportation sector.
    May 09, 2013   doi: 10.1111/tgis.12017   open full text
  • Location Based Social Networks – Definition, Current State of the Art and Research Agenda.
    Oliver Roick, Susanne Heuser.
    Transactions in GIS. May 03, 2013
    The growing penetration of GPS equipped smartphones allowing users to constantly share geographic information on their current whereabouts has led the way to an augmentation of existing Social Network Sites with location‐based features or the creation of new ones exclusively around geographic information. Within these Location Based Social Networks vast amounts of geographic information are allocated, which attracted the attention of researchers with various scientific backgrounds. This article presents a comprehensive definition of this special type of Social Network Site and an overview of research activities, which are currently conducted using the data. Finally, a research agenda for GIScience is drawn from existing research directions.
    May 03, 2013   doi: 10.1111/tgis.12032   open full text
  • Simulating Spatial Dynamics and Processes in a Retail Gasoline Market: An Agent‐Based Modeling Approach.
    Alison J. Heppenstall, Kirk Harland, Andrew N. Ross, Dan Olner.
    Transactions in GIS. April 22, 2013
    Simulating the dynamics and processes within a spatially influenced retail market, such as the retail gasoline market, is a highly challenging research area. Current approaches are limited through their inability to model the impact of supplier or consumer behavior over both time and space. Agent‐based models (ABMs) provide an alternative approach that overcomes these problems. We demonstrate how knowledge of retail pricing is extended by using a ‘hybrid’ model approach: an agent model for retailers and a spatial interaction model for consumers. This allows the issue of spatial competition between individual retailers to be examined in a way only accessible to agent‐based models, allowing each model retailer autonomous control over optimizing their price. The hybrid model is shown to be successful at recreating spatial pricing dynamics at a national scale, simulating the effects of a rise in crude oil prices as well as accurately predicting which retailers were most susceptible to closure over a 10‐year period.
    April 22, 2013   doi: 10.1111/tgis.12027   open full text
  • Accessibility Futures.
    Paul Anderson, David Levinson, Pavithra Parthasarathi.
    Transactions in GIS. April 18, 2013
    This study uses accessibility as a performance measure to evaluate a matrix of future land use and network scenarios for planning purposes. The concept of accessibility dates to the 1950s, but this type of application to transportation planning is new. Previous research has established the coevolution of transportation and land use, demonstrated the dependence of accessibility on both, and made the case for the use of accessibility measures as a planning tool. This study builds off of these findings by demonstrating the use of accessibility‐based performance measures in the Twin Cities Metropolitan Area. This choice of performance measure also allows for transit and highway networks to be compared side‐by‐side. For roadway modeling, zone‐to‐zone travel time matrix was computed using stochastic user equilibrium (SUE) assignment with travel time feedback to trip distribution. A database of schedules was used on the transit networks to assign transit routes. This travel time data was joined with the land use data from each scenario to obtain the employment, population, and labor accessibility from each traffic analysis zone (TAZ) within specified time ranges. Tables of person‐weighted accessibility were computed for 20 minutes with zone population as the weight for employment accessibility and zone employment as the weight for population and labor accessibility. Maps of accessibility by zone were produced to show the spatial distribution of accessibility across the region. The results show that a scenario where population and employment growth are concentrated in the center of the metropolitan area would produce the highest accessibility no matter which transportation network changes are made. However, another scenario which concentrates population growth in the center of the metropolitan area and shifts employment growth to the periphery consistently outperforms the scenario representing the projected 2030 land use without any growth management strategy.
    April 18, 2013   doi: 10.1111/tgis.12024   open full text
  • The Influence of Digital Surface Model Choice on Visibility‐based Mobile Geospatial Applications.
    Sam Meek, James Goulding, Gary Priestnall.
    Transactions in GIS. April 10, 2013
    In this work we investigate the effectiveness of different types of visibility models for use within location‐based services. This article outlines the methodology and results for our experiments, which were designed to understand the accuracy and effects of model choices for mobile visibility querying. Harnessing a novel mobile media consumption and authoring application called Zapp, the levels of accuracy of various digital surface representations used by a line of sight visibility algorithm are extensively examined by statistically assessing randomly sampled viewing sites across the 1 km2 study area, in relation to points of interest (POI) across the University of Nottingham campus. Testing was carried out on three different surface models derived from 0.5 m LiDAR data by visiting physical sites on each surface model with 14 random point of interest masks being viewed from between 10 and 16 different locations, totalling 190 data points. Each site was ground‐truthed by determining whether a given POI could be seen by the user and could also be identified by the mobile device. Our experiments in a semi‐urban area show that choice of surface model has important implications for mobile applications that utilize visibility in geospatial query operations.
    April 10, 2013   doi: 10.1111/tgis.12021   open full text
  • Urban Structure Generalization in Multi‐Agent Process by Use of Reactional Agents.
    Jérémy Renard, Cécile Duchêne.
    Transactions in GIS. March 19, 2013
    This article proposes an improvement of automated cartographic generalization using multi‐agent sytems in urban areas. Indeed the AGENT model, whose robustness has been tested and approved through the European project AGENT, gives very good results in generalizing dense urban areas by means of enlargement, removal and displacement of buildings. But this model does not tackle the question of including particular structures like building alignments in the process, which is a crucial issue. The problem is that integrating such structures does not fit into the accurate top‐down hierarchy of urban agents. In order to face this problem, we propose to partly re‐engineer the model by introducing the concept of reactional agents whose behavior is very different from hierarchical agents of the original model as they use bottom‐up activation. In this view, urban alignment is considered to be a reactional agent activated only by its inner buildings, which generalizes the aligned buildings together into one entire structure. Associating reactional alignment behavior with new generalization actions on alignments significantly improves the model and gives better results in dense urban areas. Moreover, the idea could probably be used for other applications.
    March 19, 2013   doi: 10.1111/tgis.12018   open full text
  • Analyzing Relatedness by Toponym Co‐Occurrences on Web Pages.
    Yu Liu, Fahui Wang, Chaogui Kang, Yong Gao, Yongmei Lu.
    Transactions in GIS. March 19, 2013
    This research proposes a method for capturing “relatedness between geographical entities” based on the co‐occurrences of their names on web pages. The basic assumption is that a higher count of co‐occurrences of two geographical places implies a stronger relatedness between them. The spatial structure of China at the provincial level is explored from the co‐occurrences of two provincial units in one document, extracted by a web information retrieval engine. Analysis on the co‐occurrences and topological distances between all pairs of provinces indicates that: (1) spatially close provinces generally have similar co‐occurrence patterns; (2) the frequency of co‐occurrences exhibits a power law distance decay effect with the exponent of 0.2; and (3) the co‐occurrence matrix can be used to capture the similarity/linkage between neighboring provinces and fed into a regionalization method to examine the spatial organization of China. The proposed method provides a promising approach to extracting valuable geographical information from massive web pages.
    March 19, 2013   doi: 10.1111/tgis.12023   open full text
  • A Triangular Form‐based Multiple Flow Algorithm to Estimate Overland Flow Distribution and Accumulation on a Digital Elevation Model.
    Petter Pilesjö, Abdulghani Hasan.
    Transactions in GIS. February 06, 2013
    In this study, we present a newly developed method for the estimation of surface flow paths on a digital elevation model (DEM). The objective is to use a form‐based algorithm, analyzing flow over single cells by dividing them into eight triangular facets and to estimate the surface flow paths on a raster DEM. For each cell on a gridded DEM, the triangular form‐based multiple flow algorithm (TFM) was used to distribute flow to one or more of the eight neighbor cells, which determined the flow paths over the DEM. Because each of the eight facets covering a cell has a constant slope and aspect, the estimations of – for example – flow direction and divergence/convergence are more intuitive and less complicated than many traditional raster‐based solutions. Experiments were undertaken by estimating the specific catchment area (SCA) over a number of mathematical surfaces, as well as on a real‐world DEM. Comparisons were made between the derived SCA by the TFM algorithm with eight other algorithms reported in the literature. The results show that the TFM algorithm produced the closest outcomes to the theoretical values of the SCA compared with other algorithms, derived more consistent outcomes, and was less influenced by surface shapes. The real‐world DEM test shows that the TFM was capable of modeling flow distribution without noticeable ‘artefacts’, and its ability to track flow paths makes it an appropriate platform for dynamic surface flow simulation.
    February 06, 2013   doi: 10.1111/tgis.12015   open full text
  • Strategically Locating Wildlife Crossing Structures for Florida Panthers Using Maximal Covering Approaches.
    Joni Downs, Mark Horner, Rebecca Loraamm, James Anderson, Hyun Kim, Dave Onorato.
    Transactions in GIS. February 05, 2013
    Crossing structures are an effective method for mitigating habitat fragmentation and reducing wildlife‐vehicle collisions, although high construction costs limit the number that can be implemented in practice. Therefore, optimizing the placement of crossing structures in road networks is suggested as a strategic conservation planning method. This research explores two approaches for using the maximal covering location problem (MCLP) to determine optimal sites to install new wildlife crossing structures. The first approach is based on records of traffic mortality, while the second uses animal tracking data for the species of interest. The objective of the first is to cover the maximum number of collision sites, given a specified number of proposed structures to build, while the second covers as many animal tracking locations as possible under a similar scenario. These two approaches were used to locate potential wildlife crossing structures for endangered Florida panthers (Puma concolor coryi) in Collier, Lee, and Hendry Counties, Florida, a population whose survival is threatened by excessive traffic mortality. Historical traffic mortality records and an extensive radio‐tracking dataset were used in the analyses. Although the two approaches largely select different sites for crossing structures, both models highlight key locations in the landscape where these structures can remedy traffic mortality and habitat fragmentation. These applications demonstrate how the MCLP can serve as a useful conservation planning tool when traffic mortality or animal tracking data are available to researchers.
    February 05, 2013   doi: 10.1111/tgis.12005   open full text
  • CONSTAnT – A Conceptual Data Model for Semantic Trajectories of Moving Objects.
    Vania Bogorny, Chiara Renso, Artur Ribeiro Aquino, Fernando Lucca Siqueira, Luis Otavio Alvares.
    Transactions in GIS. February 05, 2013
    Several works have been proposed in the last few years for raw trajectory data analysis, and some attempts have been made to define trajectories from a more semantic point of view. Semantic trajectory data analysis has received significant attention recently, but the formal definition of semantic trajectory, the set of aspects that should be considered to semantically enrich trajectories and a conceptual data model integrating these aspects from a broad sense is still missing. This article presents a semantic trajectory conceptual data model named CONSTAnT, which defines the most important aspects of semantic trajectories. We believe that this model will be the foundation for the design of semantic trajectory databases, where several aspects that make a trajectory “semantic” are taken into account. The proposed model includes the concepts of semantic subtrajectory, semantic points, geographical places, events, goals, environment and behavior, to create a general concept of semantic trajectory. The proposed model is the result of several years of work by the authors in an effort to add more semantics to raw trajectory data for real applications. Two application examples and different queries show the flexibility of the model for different domains.
    February 05, 2013   doi: 10.1111/tgis.12011   open full text
  • The Co‐evolution of Residential Segregation and the Built Environment at the Turn of the 20th Century: A Schelling Model.
    Seth Spielman, Patrick Harrison.
    Transactions in GIS. February 05, 2013
    To what degree does the built environment of cities shape the social environment? In this article we use a Schelling‐like agent‐based model to consider how changes to the built environment of cities relate to changes in residential segregation by income and ethnicity. To develop this model we exploit insights from a high resolution historical GIS which maps 100% of the population of Newark, NJ in 1880. Newark in 1880 had a complex social landscape characterized by areas of significant social and economic segregation and areas of relative integration. We develop a Schelling model capable of reproducing these residential patterns. We use this model to explore the decentralization of housing, a specific phenomenon associated with the demise of the walking city in the late 19th century. Holding agent preferences constant, but allowing the landscape of the Schelling model to evolve in ways that reflect historical changes to the built environment, produces changes to the social landscape that are also consistent with history. Our work suggests that changes in residential segregation do not necessarily imply changes to individual attitudes and preferences. Changes in residential segregation can be generated by changes to the built environment, specifically the geographic distribution of housing.
    February 05, 2013   doi: 10.1111/tgis.12014   open full text
  • A Parcel Shape Index for Use in Land Consolidation Planning.
    Demetris Demetriou, Linda See, John Stillwell.
    Transactions in GIS. February 05, 2013
    Area shape analysis has been a subject of focus for research in geography and other disciplines for many years. However, existing area shape indices present significant weaknesses for the analysis of land parcels in an agricultural context as they do not measure shape in an appropriate, reliable or explicit manner. This article presents a new parcel shape index (PSI) which integrates six geometric parameters through multi‐attribute decision‐making, combined with value functions for parameter standardization. The superior performance of the new PSI in relation to three existing indices is demonstrated through a case study area in Cyprus. The methodology can be applied in other contexts aimed at assessing the quality of a particular shape compared to an optimum.
    February 05, 2013   doi: 10.1111/j.1467-9671.2012.01371.x   open full text
  • Adaptive Zoning for Transport Mode Choice Modeling.
    Alex Hagen‐Zanker, Ying Jin.
    Transactions in GIS. January 14, 2013
    Adaptive zoning is a recently introduced method for improving computer modeling of spatial interactions and movements in the transport network. Unlike traditional zoning, where geographic locations are defined by one single universal plan of discrete land parcels or ‘zones’ for the study area, adaptive zoning establishes a compendium of different zone plans, each of which is applicable to one journey origin or destination only. These adaptive zone plans are structured to represent strong spatial interactions in proportionately more detail than weaker ones. In recent articles, it has been shown that adaptive zoning improves, by a large margin, the scalability of models of spatial interaction and road traffic assignment. This article confronts the method of adaptive zoning with an application of the scale and complexity for which it was intended, namely an application of mode choice modeling that at the same time requires a large study area and a fine‐grained zone system. Our hypothesis is that adaptive zoning can significantly improve the accuracy of mode choice modeling because of its enhanced sensitivity to the geographic patterns and scales of spatial interaction. We test the hypothesis by investigating the performance of three alternative models: (1) a spatially highly detailed model that is permissible to the maximum extent by available data, but requires a high computational load that is generally out of reach for rapid turnaround of policy studies; (2) a mode choice model for the same area, but reducing the computational load by 90% by using a traditional zone system consisting of fewer zones; and (3) a mode choice model that also reduces the computational load by 90%, but based on adaptive zoning instead. The tests are carried out on the basis of a case study that uses the dataset from the London Area Transport Survey. Using the first model as a benchmark, it is found that for a given computational load, the model based on adaptive zoning contains about twice the amount of information of the traditional model, and model parameters on adaptive zoning principles are more accurate by a factor of six to eight. The findings suggest that adaptive zoning has a significant potential in enhancing the accuracy of mode choice modeling at the city or city‐region scale.
    January 14, 2013   doi: 10.1111/j.1467-9671.2012.01372.x   open full text
  • A Patch‐based Cellular Automaton for Simulating Land‐use Changes at Fine Spatial Resolution.
    Fang Wang, Danielle J. Marceau.
    Transactions in GIS. January 08, 2013
    While cellular automata have become popular tools for modeling land‐use changes, there is a lack of studies reporting their application at very fine spatial resolutions (e.g. 5 m resolution). Traditional cell‐based CA do not generate reliable results at such resolutions because single cells might only represent components of land‐use entities (i.e. houses or parks in urban residential areas), while recently proposed entity‐based CA models usually ignore the internal heterogeneity of the entities. This article describes a patch‐based CA model designed to deal with this problem by integrating cell and object concepts. A patch is defined as a collection of adjacent cells that might have different attributes, but that represent a single land‐use entity. In this model, a transition probability map was calculated at each cell location for each land‐use transition using a weight of evidence method; then, land‐use changes were simulated by employing a patch‐based procedure based on the probability maps. This CA model, along with a traditional cell‐based model were tested in the eastern part of the Elbow River watershed in southern Alberta, Canada, an area that is under considerable pressure for land development due to its proximity to the fast growing city of Calgary. The simulation results for the two models were compared to historical data using visual comparison, Ksimulation indices, and landscape metrics. The results reveal that the patch‐based CA model generates more compact and realistic land‐use patterns than the traditional cell‐based CA. The Ksimulation values indicate that the land‐use maps obtained with the patch‐based CA are in higher agreement with the historical data than those created by the cell‐based model, particularly regarding the location of change. The landscape metrics reveal that the patch‐based model is able to adequately capture the land‐use dynamics as observed in the historical data, while the cell‐based CA is not able to provide a similar interpretation. The patch‐based approach proposed in this study appears to be a simple and valuable solution to take into account the internal heterogeneity of land‐use classes at fine spatial resolutions and simulate their transitions over time.
    January 08, 2013   doi: 10.1111/tgis.12009   open full text
  • Using Pattern‐oriented Modeling (POM) to Cope with Uncertainty in Multi‐scale Agent‐based Models of Land Change.
    Nicholas R. Magliocca, Erle C. Ellis.
    Transactions in GIS. January 08, 2013
    Local land‐use and ‐cover changes (LUCCs) are the result of both the decisions and actions of individual land‐users, and the larger global and regional economic, political, cultural, and environmental contexts in which land‐use systems are embedded. However, the dearth of detailed empirical data and knowledge of the influences of global/regional forces on local land‐use decisions is a substantial challenge to formulating multi‐scale agent‐based models (ABMs) of land change. Pattern‐oriented modeling (POM) is a means to cope with such process and parameter uncertainty, and to design process‐based land change models despite a lack of detailed process knowledge or empirical data. POM was applied to a simplified agent‐based model of LUCC to design and test model relationships linking global market influence to agents’ land‐use decisions within an example test site. Results demonstrated that evaluating alternative model parameterizations based on their ability to simultaneously reproduce target patterns led to more realistic land‐use outcomes. This framework is promising as an agent‐based virtual laboratory to test hypotheses of how and under what conditions driving forces of land change differ from a generalized model representation depending on the particular land‐use system and location.
    January 08, 2013   doi: 10.1111/tgis.12012   open full text
  • Spatial Modeling of the Black Death in Sweden.
    Lars Skog, Hans Hauska.
    Transactions in GIS. January 02, 2013
    The purpose of this work is to determine whether spatial modeling can be used to model the spread of the Black Death. The study is limited to models for the propagation of the disease in Sweden in 1350. Geographic data of Swedish water bodies and medieval road networks, historical data on the population in Swedish parishes, including their medieval boundaries, along with historical notes and disease characteristics, were used to build alternative models for spatial distribution. Three different models are presented: one radial, one cost‐based and one combining network analysis and radial propagation. Simulations were made to depict different scenarios on the spread of the disease, as well as the drastic changes in the overall population of Sweden, over a couple of hundred years. For purpose of validation the population decrease estimated in each parish is compared with independent historical documents. Results from model scenarios are visualized in maps of propagation, animated video sequences and a web map service. Our analyses clearly demonstrate the power of spatial analysis and geographic information systems to describe, model and visualize epidemiologic processes in space and time.
    January 02, 2013   doi: 10.1111/j.1467-9671.2012.01369.x   open full text
  • Finding Science with Science: Evaluating a Domain and Scientific Ontology User Interface for the Discovery of Scientific Resources.
    Kristin Stock, Vera Karasova, Anne Robertson, Guillaume Roger, Mark Small, Mohamed Bishr, Jens Ortmann, Tim Stojanovic, Femke Reitsma, Lukasz Korczynski, Boyan Brodaric, Zoe Gardner.
    Transactions in GIS. December 26, 2012
    Current approaches to the discovery of scientific resources (publications, data sets and web services) are dominated by keyword search. These approaches do not allow scientists to search on the deeper semantics of scientific resources, or to discover resources on the basis of the scientific approaches taken. This article evaluates a user interface that allows users to discover scientific resources through structured knowledge in the form of ontologies describing the domain and the scientific knowledge inherent within the scientific resource, and also through informal user tags. These combined capabilities provide scientists with new and powerful options for resource discovery. A qualitative user evaluation explored how scientists felt about the approach for resource discovery in the context of their scientific work. The study showed that marine scientists were enthusiastic about the capabilities of such an approach and appreciated the ability to browse the visual structure of the knowledge and query on scientific method but, overall, preferred the use of tags over ontologies. The exploratory nature of the user study was used to identify future directions for such improvements.
    December 26, 2012   doi: 10.1111/j.1467-9671.2012.01370.x   open full text
  • Access and Equity in Greenspace Provision: A Comparison of Methods to Assess the Impacts of Greening Vacant Land.
    Megan Heckert.
    Transactions in GIS. December 26, 2012
    This research explores three methods of measuring access to greenspace in Philadelphia and their implications for assessing equity in access based on race and socioeconomic status. These three methods are then used to assess the impacts of a vacant land greening program which turns vacant lots into temporary greenspaces. This research explores the differences between findings when access to greenspace is measured based on distance to any greenspace, total amount of greenspace to which residents have access, or a hybrid measure in which access is determined based on proximity to a threshold amount of greenspace. Not only do assessments of equity differ between the three approaches, but so do determinations of the impact of greening vacant land. Blacks, Hispanics and renters are more likely to live close to a public greenspace than whites or homeowners, but live in proximity to smaller overall amounts of greenspace. Greening vacant land increases the proportion of all residents who live within walking distance of a greenspace and lessens but does not eliminate differences in total greenspace access. The greatest effects of greening vacant land are seen in addressing differences in relative likelihood of having access to a threshold amount of greenspace.
    December 26, 2012   doi: 10.1111/tgis.12000   open full text
  • Out‐of‐Core GPU‐based Change Detection in Massive 3D Point Clouds.
    Rico Richter, Jan Eric Kyprianidis, Jürgen Döllner.
    Transactions in GIS. December 05, 2012
    If sites, cities, and landscapes are captured at different points in time using technology such as LiDAR, large collections of 3D point clouds result. Their efficient storage, processing, analysis, and presentation constitute a challenging task because of limited computation, memory, and time resources. In this work, we present an approach to detect changes in massive 3D point clouds based on an out‐of‐core spatial data structure that is designed to store data acquired at different points in time and to efficiently attribute 3D points with distance information. Based on this data structure, we present and evaluate different processing schemes optimized for performing the calculation on the CPU and GPU. In addition, we present a point‐based rendering technique adapted for attributed 3D point clouds, to enable effective out‐of‐core real‐time visualization of the computation results. Our approach enables conclusions to be drawn about temporal changes in large highly accurate 3D geodata sets of a captured area at reasonable preprocessing and rendering times. We evaluate our approach with two data sets from different points in time for the urban area of a city, describe its characteristics, and report on applications.
    December 05, 2012   doi: 10.1111/j.1467-9671.2012.01362.x   open full text