A 3D Integral Data Model for Subsurface Entities Based on Extended GTP

3D integral modeling of geology-excavation entities is an important issue of 3D GIS. Based on the past research results of Generalized Tri-Prism (GTP), its modeling object, constituent primitives and topological description mode are extended and amended. According to the extended-GTP model, 8 kinds of geometric primitives and 6 kinds of geological primitives are abstracted from geology-excavation entities, and 3D integral model of geology-excavation entities is put forward. Considering the characteristics of borehole data and GTP modeling process, the 3D constructing inference rule of geological model, which can solve referencing and automatic modeling problem of complex geological entities like bifurcation, pinch-out and fault, is detailed studied. In order to ensure the uniqueness, liability and local operation of converting from GTP into tetrahedron, the Smallest Vertex Identifier (SVID) method is proposed. An experimental system of 3D integral modeling of geology-excavation entities is developed and practically applied in Central Business District (CBD) in Beijing.