Spatial Objects Generalization Algorithm in Three Dimension Level of Detail GIS

An improved R-Tree （IR-tree） strategy of data organization and the corresponding algorithm of generalization in 3D level of detail GIS are presented in this paper. This algorithm builds the IR-tree based on the static qualities of spatial objects firstly,and then re-calculates the dynamic qualities of these spatial objects by the current distances of the viewpoint,resorts the objects list,and outputs the spatial objects based on the current scale and viewpoint dynamically by the algorithm 2 and algorithm 3 introduced in the paper.Experiments show that the algorithm could achieve more accurate display results and meet the current requirements in 3D GIS applications.