ABSTRACT

To solve the problem that existing data structure cannot support the multi-scale representation of multi-dimensional spatial data in Web Geographic Information System (WebGIS), a modified data structure has been put forward: (1) getting the main tree from the deformation of the index structure of region quadtree partitioned on the basis of the rule of pyramid structure; (2) possessing the sub-tree structure supporting the overlap of multi-dimensional spatial data; (3)reflecting the changes in spatial resolution using the depth of the tree; (4)all the nodes of the tree are the container of spatial objects. The necessity of generating the index is analyzed which is described. The algorithm for data generation of index structure, the support to the multi-dimensional data and the query process is discussed. For the same data source, some comparative experiments are provided using this structure and layer, and the result shows that this index method can represent and search massive multi-dimensional spatial data effectively in WebGIS. The structure has been used in Shanghai multi-dimensional WebGIS system.