3D Urban Geological Modeling and its Application in China: Technologies and Developments

3D urban geological modeling is an important research issue with the studying of the digital city in China. In view of the deficiencies of present modeling methods, a new method to model 3D urban geological body including faults based on generalized tri-prism (GTP) model is presented. Four geological knowledge inference rules about urban 3D urban geological modeling are put forward. The method mainly includes three steps: (a) Process and organize the borehole data; (b) Generate Delaunay TIN (D-TIN) of the geological upper surface according to borehole´s collar data; (c) Extend each triangle of the D-TINs down into GTP along borehole line referring to the four geological knowledge inference rules. In order to improve the flexibility and the interactivity of 3D visualization, a 3D interactive environment is provided. The application for 3D geosciences modeling and 3D visualization including 3D interactive visualization, aided design and spatial inquiry etc are introduced. A real-3D geosciences modeling system, GeoMo3D, is developed with VC++, OpenGL and SQL sever. An actual 3D geological model of an exploring district of University City, Guangzhou, is shown as a case.