Cartography and Geographic Information Science, Dec 16, 2014
In the representation of topographic data, the distribution of hydrographic networks should be co... more In the representation of topographic data, the distribution of hydrographic networks should be constrained by the contour model's landform features. During the integration of topographic databases, however, spatial conflicts may destroy these constraints, generating inconsistencies. This study presents a method to detect and correct inconsistencies between river networks and contour data by spatial knowledge. First, structured terrain features are extracted from the contour-based geometric representation and matching relationships between rivers and contours are constructed based on spatial knowledge of the distribution of rivers and talwegs. We then propose a distance metric for measuring differences and identifying inconsistencies between the matched river and contour features. Three correction approaches are provided for different inconsistency situations, including river adjustment referenced to the contour, contour adjustment referenced to the river and adjustment of both river and contour to middle positions. We apply the proposed method to the integration and maintenance of national topographic infrastructure in order to demonstrate its effectiveness.
This paper focuses on the issues of categorical database generalization and emphasizes the roles ... more This paper focuses on the issues of categorical database generalization and emphasizes the roles of supporting data model, integrated data model, spatial analysis and semantic analysis in database generalization. The framework contents of categorical database generalization transformation are defined. The paper presents an integrated spatial supporting data structure, a semantic supporting model and similarity model for categorical database generalization. The
Isprs Journal of Photogrammetry and Remote Sensing, Mar 1, 2010
As an important method of terrain representation, a DEM usually needs to be generalized at multip... more As an important method of terrain representation, a DEM usually needs to be generalized at multiple resolutions in order to adapt to different applications. The preservation of main landscape features is an important constraint in DEM generalization. The traditional generalization method based on signal processing by resampling or low-pass filtering is just a data compression operation rather than the abstraction
The classification by extracting of remote sensing (RS) data is the primary information source fo... more The classification by extracting of remote sensing (RS) data is the primary information source for GIS in land resource application. Automatic and accurate mapping of region LUCC from high spatial resolution satellite image is still a challenge. The paper discussed remote sensing image data classification techniques based on C4.5 algorithm and rough sets and the combination of C4.5 algorithm and rough sets. On the basis of the theories and methods of spatial data mining, we improve the classification accuracy. Finally validates its effectiveness taking a test area as example. We took the outskirts of Fuzhou with complicated land use in Fujian Province as study area. The classification rules are discovered from the samples through decision tree C4.5 algorithm, Rough Sets and both with together, which integrates spectral, textural and the topography characters. And the classification test is performed based on these rules. The traditional maximum likelihood classification is also compared to check the classification accuracy. The results have shown that the accuracy of classification based on knowledge is markedly higher than the traditional maximum likelihood classification. Especially the method based on combine Rough Sets and decision tree C4.5 algorithm is the best.
Accessibility analysis usually requires special models of spatial location analysis based on some... more Accessibility analysis usually requires special models of spatial location analysis based on some geometric constructions, such as Voronoi diagram (abbreviated to VD). There are many achievements in classic Voronoi model research, however suffering from the following limitations for location-based services (LBS) applications. (1) It is difficult to objectively reflect the actual service areas of facilities by using traditional planar VDs, because human activities in LBS are usually constrained only to the network portion of the planar space.
As the representation of terrain surface and height information, the contour data has the strict ... more As the representation of terrain surface and height information, the contour data has the strict constraint relationship with the distribution of river network. In spatial data integration and matching, the inconsistency usually occurs between the river network and contour generating "river climbing uphill". This study presents a method to build the matching relationship and to correct the inconsistency between river network and contour data. Based on Delaunay triangulation, the terrain landform features are extracted and by bend analysis build the matching relations between river network and contour. According to different inconsistency situations, we offer two correction approaches depending on which data is precise, which includes the river network displacement referenced to the contour and the opposite.
ABSTRACT Central Business District (CBD) is the core area of urban planning and decision manageme... more ABSTRACT Central Business District (CBD) is the core area of urban planning and decision management. The cartographic definition and representation of CBD is of great significance in studying the urban development and its functions. In order to facilitate these processes, the Kernel Density Estimation (KDE) is a very efficient tool as it considers the decay impact of services and allows the enrichment of the information from a very simple input scatter plot to a smooth output density surface. However, most existing methods of density analysis consider geographic events in a homogeneous and isotropic space under Euclidean space representation. Considering the case that the physical movement in the urban environment is usually constrained by a street network, we propose a different method for the delimitation of CBD with network configurations. First, starting from the locations of central activities, a concentration index is presented to visualize the functional urban environment by means of a density surface, which is refined with network distances rather than Euclidean ones. Then considering the specialties of network distance computation problem, an efficient way supported by flow extension simulation is proposed. Taking Shenzhen and Guangzhou, two quite developed cities in China as two case studies, we demonstrate the easy implementation and practicability of our method in delineating CBD.
2009 Fifth International Conference on Natural Computation, 2009
... MENG Ni-na, AI Ting-hua School of Resource and Environmental Science Wuhan University Wuhan, ... more ... MENG Ni-na, AI Ting-hua School of Resource and Environmental Science Wuhan University Wuhan, China zhouxdm@163.com MENG Ni-na, LI Rong-juan College of Geology Engineering and Geomatics Chang'an University Xi'an, China zhouxdm@163.com ...
Studies the regularity for changes of spatial relations based on the gradual changes of spatial l... more Studies the regularity for changes of spatial relations based on the gradual changes of spatial location between two regional objects. Generates the conceptual neighborhood model of spatial relations like concentric circles, and provides the formal representation for them using graph theory. Based on the idea of "topylogy matters, metric refines"[1], the model uses topological relations as basic classification and different
ABSTRACT As a well-known geometric construction, Voronoi diagrams play an important role in appli... more ABSTRACT As a well-known geometric construction, Voronoi diagrams play an important role in applications of location-based services, such as accessibility analysis and nearest route detection. Because the movement in urban areas is constrained by the street network under certain transformation conditions, it is necessary to construct a new type of Voronoi diagram based on the network path distance rather than the conventional Euclidean distance. This study presents a constrained network Voronoi diagram using stream flowing ideas. A new distance, the “lixel distance”, is defined to measure the travel cost by subdividing the edge into small linear segments constrained by travel speed and other traffic conditions. Based on the stream of flowing ideas, the algorithm lets all studied source streams spread over the network paths until meeting other streams or arriving at the end of an edge. This process is similar to the expansion operation in the raster geo-processing of Euclidean space. By comparison with the previous approaches in a static environment, this algorithm can be applied to accurately estimate service areas for facilities in real time and to easily add constraints of movement and traffic, such as one-way traffic and restricted street access. The experiment on real POI data to find the service areas in Guangzhou city, China shows that the proposed algorithm is efficient and effective.
Cartography and Geographic Information Science, Dec 16, 2014
In the representation of topographic data, the distribution of hydrographic networks should be co... more In the representation of topographic data, the distribution of hydrographic networks should be constrained by the contour model's landform features. During the integration of topographic databases, however, spatial conflicts may destroy these constraints, generating inconsistencies. This study presents a method to detect and correct inconsistencies between river networks and contour data by spatial knowledge. First, structured terrain features are extracted from the contour-based geometric representation and matching relationships between rivers and contours are constructed based on spatial knowledge of the distribution of rivers and talwegs. We then propose a distance metric for measuring differences and identifying inconsistencies between the matched river and contour features. Three correction approaches are provided for different inconsistency situations, including river adjustment referenced to the contour, contour adjustment referenced to the river and adjustment of both river and contour to middle positions. We apply the proposed method to the integration and maintenance of national topographic infrastructure in order to demonstrate its effectiveness.
This paper focuses on the issues of categorical database generalization and emphasizes the roles ... more This paper focuses on the issues of categorical database generalization and emphasizes the roles of supporting data model, integrated data model, spatial analysis and semantic analysis in database generalization. The framework contents of categorical database generalization transformation are defined. The paper presents an integrated spatial supporting data structure, a semantic supporting model and similarity model for categorical database generalization. The
Isprs Journal of Photogrammetry and Remote Sensing, Mar 1, 2010
As an important method of terrain representation, a DEM usually needs to be generalized at multip... more As an important method of terrain representation, a DEM usually needs to be generalized at multiple resolutions in order to adapt to different applications. The preservation of main landscape features is an important constraint in DEM generalization. The traditional generalization method based on signal processing by resampling or low-pass filtering is just a data compression operation rather than the abstraction
The classification by extracting of remote sensing (RS) data is the primary information source fo... more The classification by extracting of remote sensing (RS) data is the primary information source for GIS in land resource application. Automatic and accurate mapping of region LUCC from high spatial resolution satellite image is still a challenge. The paper discussed remote sensing image data classification techniques based on C4.5 algorithm and rough sets and the combination of C4.5 algorithm and rough sets. On the basis of the theories and methods of spatial data mining, we improve the classification accuracy. Finally validates its effectiveness taking a test area as example. We took the outskirts of Fuzhou with complicated land use in Fujian Province as study area. The classification rules are discovered from the samples through decision tree C4.5 algorithm, Rough Sets and both with together, which integrates spectral, textural and the topography characters. And the classification test is performed based on these rules. The traditional maximum likelihood classification is also compared to check the classification accuracy. The results have shown that the accuracy of classification based on knowledge is markedly higher than the traditional maximum likelihood classification. Especially the method based on combine Rough Sets and decision tree C4.5 algorithm is the best.
Accessibility analysis usually requires special models of spatial location analysis based on some... more Accessibility analysis usually requires special models of spatial location analysis based on some geometric constructions, such as Voronoi diagram (abbreviated to VD). There are many achievements in classic Voronoi model research, however suffering from the following limitations for location-based services (LBS) applications. (1) It is difficult to objectively reflect the actual service areas of facilities by using traditional planar VDs, because human activities in LBS are usually constrained only to the network portion of the planar space.
As the representation of terrain surface and height information, the contour data has the strict ... more As the representation of terrain surface and height information, the contour data has the strict constraint relationship with the distribution of river network. In spatial data integration and matching, the inconsistency usually occurs between the river network and contour generating "river climbing uphill". This study presents a method to build the matching relationship and to correct the inconsistency between river network and contour data. Based on Delaunay triangulation, the terrain landform features are extracted and by bend analysis build the matching relations between river network and contour. According to different inconsistency situations, we offer two correction approaches depending on which data is precise, which includes the river network displacement referenced to the contour and the opposite.
ABSTRACT Central Business District (CBD) is the core area of urban planning and decision manageme... more ABSTRACT Central Business District (CBD) is the core area of urban planning and decision management. The cartographic definition and representation of CBD is of great significance in studying the urban development and its functions. In order to facilitate these processes, the Kernel Density Estimation (KDE) is a very efficient tool as it considers the decay impact of services and allows the enrichment of the information from a very simple input scatter plot to a smooth output density surface. However, most existing methods of density analysis consider geographic events in a homogeneous and isotropic space under Euclidean space representation. Considering the case that the physical movement in the urban environment is usually constrained by a street network, we propose a different method for the delimitation of CBD with network configurations. First, starting from the locations of central activities, a concentration index is presented to visualize the functional urban environment by means of a density surface, which is refined with network distances rather than Euclidean ones. Then considering the specialties of network distance computation problem, an efficient way supported by flow extension simulation is proposed. Taking Shenzhen and Guangzhou, two quite developed cities in China as two case studies, we demonstrate the easy implementation and practicability of our method in delineating CBD.
2009 Fifth International Conference on Natural Computation, 2009
... MENG Ni-na, AI Ting-hua School of Resource and Environmental Science Wuhan University Wuhan, ... more ... MENG Ni-na, AI Ting-hua School of Resource and Environmental Science Wuhan University Wuhan, China zhouxdm@163.com MENG Ni-na, LI Rong-juan College of Geology Engineering and Geomatics Chang'an University Xi'an, China zhouxdm@163.com ...
Studies the regularity for changes of spatial relations based on the gradual changes of spatial l... more Studies the regularity for changes of spatial relations based on the gradual changes of spatial location between two regional objects. Generates the conceptual neighborhood model of spatial relations like concentric circles, and provides the formal representation for them using graph theory. Based on the idea of "topylogy matters, metric refines"[1], the model uses topological relations as basic classification and different
ABSTRACT As a well-known geometric construction, Voronoi diagrams play an important role in appli... more ABSTRACT As a well-known geometric construction, Voronoi diagrams play an important role in applications of location-based services, such as accessibility analysis and nearest route detection. Because the movement in urban areas is constrained by the street network under certain transformation conditions, it is necessary to construct a new type of Voronoi diagram based on the network path distance rather than the conventional Euclidean distance. This study presents a constrained network Voronoi diagram using stream flowing ideas. A new distance, the “lixel distance”, is defined to measure the travel cost by subdividing the edge into small linear segments constrained by travel speed and other traffic conditions. Based on the stream of flowing ideas, the algorithm lets all studied source streams spread over the network paths until meeting other streams or arriving at the end of an edge. This process is similar to the expansion operation in the raster geo-processing of Euclidean space. By comparison with the previous approaches in a static environment, this algorithm can be applied to accurately estimate service areas for facilities in real time and to easily add constraints of movement and traffic, such as one-way traffic and restricted street access. The experiment on real POI data to find the service areas in Guangzhou city, China shows that the proposed algorithm is efficient and effective.
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