A detailed landslide susceptibility map was produced in the Youfang catchment using logistic regression method with datasets developed for a geographic information system(GIS).Known as one of the most landslide-prone ...A detailed landslide susceptibility map was produced in the Youfang catchment using logistic regression method with datasets developed for a geographic information system(GIS).Known as one of the most landslide-prone areas in China, the Youfang catchment of Longnan mountain region,which lies in the transitional area among QinghaiTibet Plateau, loess Plateau and Sichuan Basin, was selected as a representative case to evaluate the frequency and distribution of landslides.Statistical relationships for landslide susceptibility assessment were developed using landslide and landslide causative factor databases.Logistic regression(LR)was used to create the landslide susceptibility maps based on a series of available data sources: landslide inventory; distance to drainage systems, faults and roads; slope angle and aspect; topographic elevation and topographical wetness index, and land use.The quality of the landslide susceptibility map produced in this paper was validated and the result can be used fordesigning protective and mitigation measures against landslide hazards.The landslide susceptibility map is expected to provide a fundamental tool for landslide hazards assessment and risk management in the Youfang catchment.展开更多
With the construction of spatial data infi'astructure, automated topographic map generalization becomes an indispensable component in the community of cartography and geographic information science. This paper descri...With the construction of spatial data infi'astructure, automated topographic map generalization becomes an indispensable component in the community of cartography and geographic information science. This paper describes a topographic map generalization system recently developed by the authors. The system has the following characteristics: 1) taking advantage of three levels of automation, i.e. fully automated generalization, batch generalization, and interactive generalization, to undertake two types of processes, i.e. intelligent inference process and repetitive operation process in generalization; 2) making use of two kinds of sources for generalizing rule library, i.e. written specifications and cartographers' experiences, to define a six-element structure to describe the rules; 3) employing a hierarchical structure for map databases, logically and physically; 4) employing a grid indexing technique and undo/redo operation to improve database retrieval and object generalization efficiency. Two examples of topographic map generalization are given to demonstrate the system. It reveals that the system works well. In fact, this system has been used for a number of projects and it has been found that a great improvement in efficiency compared with traditional map general- ization process can be achieved.展开更多
Based on the relationship among the geographic events, spatial changes and the database operations, a new automatic (semi-automatic) incremental updating approach of spatio-temporal database (STDB) named as (event-bas...Based on the relationship among the geographic events, spatial changes and the database operations, a new automatic (semi-automatic) incremental updating approach of spatio-temporal database (STDB) named as (event-based) incremental updating (E-BIU) is proposed in this paper. At first, the relationship among the events, spatial changes and the database operations is analyzed, then a total architecture of E-BIU implementation is designed, which includes an event queue, three managers and two sets of rules, each component is presented in detail. The process of the E-BIU of master STDB is described successively. An example of building’s incremental updating is given to illustrate this approach at the end. The result shows that E-BIU is an efficient automatic updating approach for master STDB.展开更多
The objective of this paper is to develop a GIS(Geographic Information System) database for Jiuzhaigou National Nature Reserve(Jiuzhaigou,hereafter) in China and demonstrate its application as a research tool.A cost-e...The objective of this paper is to develop a GIS(Geographic Information System) database for Jiuzhaigou National Nature Reserve(Jiuzhaigou,hereafter) in China and demonstrate its application as a research tool.A cost-effective procedure was developed to compile a variety of geographical and biological data of the study area in terms of popular GIS format such as shape files.These files were further calibrated and validated using field surveys data.The developed GIS database was used to quantify the distributions of the wildlife(amphibians,mammals,and birds) using the distances of the wildlife to the centerline of the bus-tour routes.The Pearson correlation coefficient was used to quantify the correlation in space between pairs of different wildlife using the number of habitats for given space contexts.An ArcObject-based macro was developed to perform the analysis.The results showed the majority of the habitats of wildlife are located in the proximity of the tour-bus routes with an average distance ranging from 564 to 894 m depending on types of wildlife.This indicates a possibility of the disturbance to the wildlife by human activities.The correlation coefficient of the wildlife ranged from 0.36 to 0.64 depending on pairs of wildlife,indicating some correlations in space.However,due to the limited sample size,the statistical significances need to be further investigated.This paper has successfully demonstrated the use of the GIS-based database as a research tool for environmental study.展开更多
With the development of mobile technology, Internet and GIS, LBS plays an important role in various applications. From the perspective of LBS, it is one of the main tasks of matching 3-dimensional spatial-temporal tra...With the development of mobile technology, Internet and GIS, LBS plays an important role in various applications. From the perspective of LBS, it is one of the main tasks of matching 3-dimensional spatial-temporal trajectories. We present an interpoiation based Modified Hausdorff Distance algorithm for 3-dimensional spatial-temporal Trajectory Matching (IMHD-ST). It adopts interpolation algorithm to shield the impact to the distance between trajectories due to different position updating porices, sampling granularity, initial position and so on in Moving Object Database (MOD). Besides, it uses MHD to deal with the implicit spatial information and structural information of weighted position updating points in various trajectories and reflects the discrepancy of moving results through the spatial distance between trajectories. In addition, it adopts temporal distance corresponding to the spatial distance between trajectories to reflect the differences including direction, speed and so on during moving process. The experimental results show that the algorithrn can reflect the trajectory similarity between 3-dimensional mobile objects more correctly, accurately and robustly.展开更多
The objective of the study was to establish spatial land evaluation for oil palm cultivation using GIS (geographic information system). The study area is situated in the KESEDAR region in the state of Kelantan, Mala...The objective of the study was to establish spatial land evaluation for oil palm cultivation using GIS (geographic information system). The study area is situated in the KESEDAR region in the state of Kelantan, Malaysia. The evaluation of the land in terms of the suitability classes were based on the method of FAO (Food and Agriculture Oganization of the United Nations). Five land qualities are important for determining the physical land suitability for oil palm; these are nutrient availability, oxygen availability, water availability, workability and availability of foothold for roots. Each of the above mentioned land qualities with associated attribute data were digitally encoded in a GIS database to create thermatic layers. Overlay operation on the layer produced resultant polygonal layer each of which is a land unit with characteristics of the land. The results from GIS overlay analyses showed that Bungor, Chat, Chempaka, Alluvium, Musang and Tok Yong series are highly suitable while Kawang series is moderately suitable for oil palm cultivation. The same results were obtained by using parametric-limitation method.展开更多
The present study shows the results of a research aimed at the knowledge of the significant features of Catania's urban environment. The complexity of the different features of the city, the several scales of represe...The present study shows the results of a research aimed at the knowledge of the significant features of Catania's urban environment. The complexity of the different features of the city, the several scales of representation, the multi-dimensional objects and the historical, anthropic, formal relations have produced different kinds of information requiring a flexible instrument that is able to transcribe images, charts, texts and symbols in a single model of representation. In the perspective of creating a fundamental cognitive framework, the research team paid attention at drawing up a GIS (Geographic Information System) for documenting and managing historic urban heritage. The idea is to have a structure able to collect data like a logic archival system or an open database, which can immediately be consulted and constantly implemented. Indeed, the aim of this GIS is to organize, manage, query and visualise the peculiar aspects which characterize Catania's architectures. Thanks to multi-directional "access-windows" it is possible to navigate through its contents (texts, drawings, 3D rendering, pictures, historical documents). The system will also allow the integration of several documents in a common geo-database up to visualise the most meaningful details. Its use could assure suitable proposals of urban transformations and coherent plans in using and/or managing heritage goods for a sustainable city development.展开更多
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(164320H101)the Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection of Chengdu University of Technology,China(SKLGP2012K012)+4 种基金the Opening Fund of Key Laboratory for Geo-hazards in Loess area(GLA2014005)the National Natural Science Foundation of China(No.40801212 and No.41201424)the 973 National Basic Research Program(Nos.2013CB733203,2013CB733204)the 863 National High-Tech Rand D Program(No.2012AA121302)the FP6 project"Mountain Risks"of the European Commission(No.MRTNCT-2006-035798)
文摘A detailed landslide susceptibility map was produced in the Youfang catchment using logistic regression method with datasets developed for a geographic information system(GIS).Known as one of the most landslide-prone areas in China, the Youfang catchment of Longnan mountain region,which lies in the transitional area among QinghaiTibet Plateau, loess Plateau and Sichuan Basin, was selected as a representative case to evaluate the frequency and distribution of landslides.Statistical relationships for landslide susceptibility assessment were developed using landslide and landslide causative factor databases.Logistic regression(LR)was used to create the landslide susceptibility maps based on a series of available data sources: landslide inventory; distance to drainage systems, faults and roads; slope angle and aspect; topographic elevation and topographical wetness index, and land use.The quality of the landslide susceptibility map produced in this paper was validated and the result can be used fordesigning protective and mitigation measures against landslide hazards.The landslide susceptibility map is expected to provide a fundamental tool for landslide hazards assessment and risk management in the Youfang catchment.
基金Under the auspices of the National Natural Science Foundation of China (No. 40301037), and a PolyU Project(G-T873)
文摘With the construction of spatial data infi'astructure, automated topographic map generalization becomes an indispensable component in the community of cartography and geographic information science. This paper describes a topographic map generalization system recently developed by the authors. The system has the following characteristics: 1) taking advantage of three levels of automation, i.e. fully automated generalization, batch generalization, and interactive generalization, to undertake two types of processes, i.e. intelligent inference process and repetitive operation process in generalization; 2) making use of two kinds of sources for generalizing rule library, i.e. written specifications and cartographers' experiences, to define a six-element structure to describe the rules; 3) employing a hierarchical structure for map databases, logically and physically; 4) employing a grid indexing technique and undo/redo operation to improve database retrieval and object generalization efficiency. Two examples of topographic map generalization are given to demonstrate the system. It reveals that the system works well. In fact, this system has been used for a number of projects and it has been found that a great improvement in efficiency compared with traditional map general- ization process can be achieved.
文摘Based on the relationship among the geographic events, spatial changes and the database operations, a new automatic (semi-automatic) incremental updating approach of spatio-temporal database (STDB) named as (event-based) incremental updating (E-BIU) is proposed in this paper. At first, the relationship among the events, spatial changes and the database operations is analyzed, then a total architecture of E-BIU implementation is designed, which includes an event queue, three managers and two sets of rules, each component is presented in detail. The process of the E-BIU of master STDB is described successively. An example of building’s incremental updating is given to illustrate this approach at the end. The result shows that E-BIU is an efficient automatic updating approach for master STDB.
基金sponsored by the Natural Science Foundation of China(Grant No.41101514)111 Project+4 种基金New Faculty Start-up Funds of Sichuan University(Grant No.JS20100324507093)the New Century Talent Support Program of the Ministry of Education of China(Grant No.NCET10-0578)International Science & Technology Cooperation Program(Grant No.2012DFG91520)Key Projects of National Science & Technology Pillar Program in the 12th 5 Years(Grant No.2013BAJ11B01)the Jiuzhaigou International Laboratory of Sichuan University,the GIS Center, and the Sustainability Research and Education Center of Sichuan University
文摘The objective of this paper is to develop a GIS(Geographic Information System) database for Jiuzhaigou National Nature Reserve(Jiuzhaigou,hereafter) in China and demonstrate its application as a research tool.A cost-effective procedure was developed to compile a variety of geographical and biological data of the study area in terms of popular GIS format such as shape files.These files were further calibrated and validated using field surveys data.The developed GIS database was used to quantify the distributions of the wildlife(amphibians,mammals,and birds) using the distances of the wildlife to the centerline of the bus-tour routes.The Pearson correlation coefficient was used to quantify the correlation in space between pairs of different wildlife using the number of habitats for given space contexts.An ArcObject-based macro was developed to perform the analysis.The results showed the majority of the habitats of wildlife are located in the proximity of the tour-bus routes with an average distance ranging from 564 to 894 m depending on types of wildlife.This indicates a possibility of the disturbance to the wildlife by human activities.The correlation coefficient of the wildlife ranged from 0.36 to 0.64 depending on pairs of wildlife,indicating some correlations in space.However,due to the limited sample size,the statistical significances need to be further investigated.This paper has successfully demonstrated the use of the GIS-based database as a research tool for environmental study.
文摘With the development of mobile technology, Internet and GIS, LBS plays an important role in various applications. From the perspective of LBS, it is one of the main tasks of matching 3-dimensional spatial-temporal trajectories. We present an interpoiation based Modified Hausdorff Distance algorithm for 3-dimensional spatial-temporal Trajectory Matching (IMHD-ST). It adopts interpolation algorithm to shield the impact to the distance between trajectories due to different position updating porices, sampling granularity, initial position and so on in Moving Object Database (MOD). Besides, it uses MHD to deal with the implicit spatial information and structural information of weighted position updating points in various trajectories and reflects the discrepancy of moving results through the spatial distance between trajectories. In addition, it adopts temporal distance corresponding to the spatial distance between trajectories to reflect the differences including direction, speed and so on during moving process. The experimental results show that the algorithrn can reflect the trajectory similarity between 3-dimensional mobile objects more correctly, accurately and robustly.
文摘The objective of the study was to establish spatial land evaluation for oil palm cultivation using GIS (geographic information system). The study area is situated in the KESEDAR region in the state of Kelantan, Malaysia. The evaluation of the land in terms of the suitability classes were based on the method of FAO (Food and Agriculture Oganization of the United Nations). Five land qualities are important for determining the physical land suitability for oil palm; these are nutrient availability, oxygen availability, water availability, workability and availability of foothold for roots. Each of the above mentioned land qualities with associated attribute data were digitally encoded in a GIS database to create thermatic layers. Overlay operation on the layer produced resultant polygonal layer each of which is a land unit with characteristics of the land. The results from GIS overlay analyses showed that Bungor, Chat, Chempaka, Alluvium, Musang and Tok Yong series are highly suitable while Kawang series is moderately suitable for oil palm cultivation. The same results were obtained by using parametric-limitation method.
文摘The present study shows the results of a research aimed at the knowledge of the significant features of Catania's urban environment. The complexity of the different features of the city, the several scales of representation, the multi-dimensional objects and the historical, anthropic, formal relations have produced different kinds of information requiring a flexible instrument that is able to transcribe images, charts, texts and symbols in a single model of representation. In the perspective of creating a fundamental cognitive framework, the research team paid attention at drawing up a GIS (Geographic Information System) for documenting and managing historic urban heritage. The idea is to have a structure able to collect data like a logic archival system or an open database, which can immediately be consulted and constantly implemented. Indeed, the aim of this GIS is to organize, manage, query and visualise the peculiar aspects which characterize Catania's architectures. Thanks to multi-directional "access-windows" it is possible to navigate through its contents (texts, drawings, 3D rendering, pictures, historical documents). The system will also allow the integration of several documents in a common geo-database up to visualise the most meaningful details. Its use could assure suitable proposals of urban transformations and coherent plans in using and/or managing heritage goods for a sustainable city development.