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1Characterization of neighborhood sensitivity of an irregular cellular automata model of urban growth
المؤلفون: Khila R. Dahal, T. Edwin Chow
المصدر: International Journal of Geographical Information Science. 29:475-497
مصطلحات موضوعية: Geographic information system, business.industry, Geography, Planning and Development, Centroid, computer.file_format, Library and Information Sciences, Grid, Cellular automaton, Outcome (probability), Geography, Sensitivity (control systems), Raster graphics, Scale (map), business, Algorithm, Cartography, computer, Information Systems
الوصف: The neighborhood definition, which determines the influence on a cell from its nearby cells within a localized region, plays a critical role in the performance of a cellular automaton CA model. Raster CA models use a cellular grid to represent geographic space, and are sensitive to the cell size and neighborhood configuration. However, the sensitivity of vector-based CAs, an alternative to the raster-based counterpart, to neighborhood type and size remains uninvestigated. The present article reports the results of a detailed sensitivity analysis of an irregular CA model of urban land use dynamics. The model uses parcel data at the cadastral scale to represent geographic space, and was implemented to simulate urban growth in Central Texas, USA. Thirty neighborhood configurations defined by types and sizes were considered in order to examine the variability in the model outcome. Results from accuracy assessments and landscape metrics confirmed the model’s sensitivity to neighborhood configurations. Furthermore, the centroid intercepted neighborhood with a buffer of 120 m produced the most accurate simulation result. This neighborhood produced scattered development while the centroid extent-wide neighborhood resulted in a clustered development predominantly near the city center.
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2
المؤلفون: Khila R. Dahal, T. Edwin Chow
المصدر: International Journal of Geographical Information Science. 28:2281-2303
مصطلحات موضوعية: Geographic information system, Operations research, business.industry, Geography, Planning and Development, Library and Information Sciences, Urban land, Cellular automaton, Automaton, Geography, Dynamics (music), Urbanization, Data model (GIS), business, Simulation, Information Systems
الوصف: Urban growth models are useful tools to understand the patterns and processes of urbanization. In recent years, the bottom-up approach of geo-computation, such as cellular automata and agent-based modeling, is commonly used to simulate urban land-use dynamics. This study has developed an integrated model of urban growth called agent-integrated irregular automata AIIA by using vector geographic information system environment i.e. both the data model and operations. The model was tested for the city of San Marcos, Texas to simulate two scenarios of urban growth. Specifically, the study aimed to answer whether incorporating commercial, industrial and institutional agents in the model and using social theories e.g. utility functions improves the conventional urban growth modeling. By validating against empirical land-use data, the results suggest that a holistic framework such as AIIA performs better than the existing irregular-automata-based urban growth modeling.
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3
المؤلفون: T. Edwin Chow, Richard C. Sadler
المصدر: Landscape and Urban Planning. 94:9-19
مصطلحات موضوعية: Knowledge management, Geographic information system, Ecology, business.industry, Computer science, Process (engineering), Delphi method, Analytic hierarchy process, Land-use planning, Management, Monitoring, Policy and Law, Multiple-criteria decision analysis, Urban Studies, Suitability analysis, business, Nature and Landscape Conservation, Suitability model
الوصف: With the emergence of geographic information systems (GIS), suitability analysis has become a modeling practice that facilitates the process of multi-criteria decision making (MCDM) by simulating the suitability of a land unit in supporting a physical or socioeconomic phenomenon. To identify and quantify the contribution of various criteria for land-use planning, however, suitability modeling relies heavily on the expert knowledge in weight assignment. Little is known about at what rate the diverse input from outside experts and local stakeholders would propagate into the suitability model and come to a consensus. The objective of this study was to investigate the development of weight assignment and suitability modeling through iterative surveying between the local stakeholders and outside experts. This research surveyed eleven field experts about the areas best suitable for future development of a scout camp in Kalkaska, MI. The expert knowledge was consulted by using the analytical hierarchy process (AHP) and a direct method of weight table. The results of suitability modeling revealed that the weight assignment between the direct method and AHP method became more different as the survey progressed. It was also observed that the most suitable area for future development slowly emerged to a consensus between the outside experts and local stakeholders through iterative survey. This research illustrated the usefulness of the Delphi method within MCDM and highlighted patches of areas adjacent to the Grass Lake that are suitable for future development.
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4
المؤلفون: T. Edwin Chow
المصدر: Transactions in GIS. 12:179-191
مصطلحات موضوعية: Distributed GIS, GIS Day, Geographic information system, Database, Application programming interface, business.industry, computer.software_genre, World Wide Web, GIS and public health, Geography, General Earth and Planetary Sciences, The Internet, Web mapping, Enterprise GIS, business, computer
الوصف: Since the launching of Maps Application Programming Interfaces (APIs) in 2005, many web developers, including geographers and non-geographers, applauded the freely adaptable tools and used them to spawn numerous Internet applications. The success of the Maps APIs is largely attributable to its no-cost policy, the availability of global data coverage, dynamic navigation, query capability, and ease of implementation. Despite its versatility in dynamic exploration of geographic data online, the existing Maps APIs lack Geographic Information System (GIS) functionalities compared to other Internet Mapping Services. The goal of this research was to review the potential of the Maps APIs for Internet GIS applications. This research employed the Google Maps API and developed a web prototype that disseminates spatial information of urban sprawl in Mundy Township, Michigan. The results revealed that both vector and raster data could be effectively represented by using the Maps API. Moreover, the Geographic Markup Language (GML) approach illustrated great potential for developing Internet GIS solutions around open specifications. This research suggested several potential solutions to expand the spectrum of GIS operations of the Maps APIs by incorporating the XML-related technology and extending the JavaScript library.
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5
المؤلفون: Michael E. Hodgson, Karen F. Gaines, T. Edwin Chow, Machelle D. Wilson
المصدر: Ecological Modelling. 189:151-167
مصطلحات موضوعية: Risk analysis, geography, Geographic information system, Resource (biology), geography.geographical_feature_category, business.industry, Ecological Modeling, Savannah River Site, Environmental resource management, Wetland, Superfund, Habitat, Environmental protection, Environmental science, Ecosystem, business
الوصف: Contamination has a dramatic impact on the health of ecosystem and habitat suitability for the inhabited flora and fauna. The Environmental Protection Agency (EPA) mandates an ecological risk assessment (ERA) that evaluates the potential adverse impact of any anthropogenic activities on the ecosystem (US Environmental Protection Agency, 1997. Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessment. EPA/630/R-021011, Washington, DC). This study provides a general framework and specific procedures to predict the contaminant exposure of midsized mammals using a geographical information system (GIS)-based Monte Carlo simulation model. The model was applied to the raccoons (Procyon lotor) on the Savannah River Site (SRS), a former nuclear production and current research facility. Habitat behavioral data of 13 radiocollared male raccoons were used to determine home range and core areas. Combined with other geographic data layers, such as distance to water, number of wetlands, and class landscape metrics, a logistic regression model was used to inductively derive the resource selection functions that define the occurrence of raccoon. The cross validation consistently revealed a high accuracy. A Monte Carlo simulation was then performed to estimate the likelihood of exposure and contaminant uptake of the species weighted by the resource selection probability. This model adopted conservative assumptions and spatial parameters. The proposed model served the purpose of assessing ecological risk and supporting decision-making. Implementation issues for a GIS-based ecological risk assessment model are discussed. © 2005 Elsevier B.V. All rights reserved.
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