3D Topology-based GIS Model (TGIS)

We propose to research, design, and develop a boundary representation based topological representation model for 3D GIS. The representation model provides a theoretically sound foundation for intra-relation 3D GIS query. The intra-relation includes all encoded topological relationships except disjoint. Also, Octree-based spatial index, Polyhedron approximation based inter-relation GIS query filtering will be integrated with the proposed topological representation. The spatial index uses a 3D space partition concept to scope down a disjoint topological relationship or unencoded intra-relation. Polyhedron approximation for inter-relation query filtering helps reduce frequency of precise 3D computation and improve overall system performance. The rationale is that 3D computation for providing a topological relation sometimes is expensive and unnecessary. Most importantly, we are adopting a 3D topological representation that can incorporate current 2D GIS representations as a subset. Therefore, a majority of current 2D GIS functionalities can be reused in the proposed 3D GIS model. Based on our design, we will take advantage of characteristics of boundary representation and use them to bridge with existing 2D GIS layer schemas. We envision the approach will smooth the migration from 2D GIS to 3D GIS without jeopardizing performance of the proposed solution.