摘要 :
In order to overcome the incontinuity and redundancy of data storage caused by the grids in representing the multi-resolution terrain, an adaptive hierarchical triangulation based on binary tree is used to represent the multi-reso...
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In order to overcome the incontinuity and redundancy of data storage caused by the grids in representing the multi-resolution terrain, an adaptive hierarchical triangulation based on binary tree is used to represent the multi-resolution terrain model. It realizes the representation of the terrain data at different levels of detail and enables data compression by local omission of data values. The structure of binary tree is stored using a bit code of the underlying binary tree, while the height data are stored using an array, and relative pointers which allow a selective tree traversal. This method realizes the continuity and reduces the data volume in data storage of multi-resolution digital elevation model (DEM), and it is possible to work directly on the compressed data. We show that significant compression rates can be obtained already for small threshold values, and in a visualization application, it is possible to extracted and drawn triangulations at interactive rates.
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摘要 :
In order to overcome the incontinuity and redundancy of data storage caused by the grids in representing the multi-resolution terrain, an adaptive hierarchical triangulation based on binary tree is used to represent the multi-reso...
展开
In order to overcome the incontinuity and redundancy of data storage caused by the grids in representing the multi-resolution terrain, an adaptive hierarchical triangulation based on binary tree is used to represent the multi-resolution terrain model. It realizes the representation of the terrain data at different levels of detail and enables data compression by local omission of data values. The structure of binary tree is stored using a bit code of the underlying binary tree, while the height data are stored using an array, and relative pointers which allow a selective tree traversal. This method realizes the continuity and reduces the data volume in data storage of multi-resolution digital elevation model (DEM), and it is possible to work directly on the compressed data. We show that significant compression rates can be obtained already for small threshold values, and in a visualization application, it is possible to extracted and drawn triangulations at interactive rates.
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摘要 :
Intelligent spatial information service in a moving environment is the necessary trend of Location-Based Services (LBS). Spatiotemporal Event Model (STEM) of Moving Objects (MO) is the precondition to realize it. This paper first ...
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Intelligent spatial information service in a moving environment is the necessary trend of Location-Based Services (LBS). Spatiotemporal Event Model (STEM) of Moving Objects (MO) is the precondition to realize it. This paper first extracts nine spatiotemporal event (STE) predicates from natural Inn guage, i.e., move_into, move_out, move_near, move_away, move_in, turn, pass_by, disappear, and appear. Then formal and symbolic representations corresponding with the predicates based on spatiotemporal relations (SR) of MOs are given respectively. Finally, a case of application based on STEM is presented. It proves that STEM is helpful to facilitate the design of an LBS system as well as the use of spatial information.
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