3D spatial query implementation method based on R-tree

3D spatial query has close relationships with human-machine interface in 3D GIS. However, its implementation method has not been discussed systematically in current literatures. According to current development in 3D GIS, this paper classifies all spatial query methods systematically. A kind of kNN query method is presented. Transformation between 3d coordinate space and 2d screen space can effectively solve the difficulty of screen pick. These methods in this paper can satisfy spatial query requirement of current 3D GIS.