Study on key technologies of three-dimensional GIS in geosciences

Some key technologies of 3D visualization GIS, which include 3D data acquiring, 3D geometry modeling, virtual reality, 3D spatial analysis, large terrain real-time roaming, indoor roaming and 3D Web GIS, can be introduced into geosciences. In this paper, analysis and management method of spatial information in 3D GIS are used in the process of basin modelling. According to geometry and mechanical distortion principle, authors develop the computer simulation and visualization technique, which use 2D seismic interpretative profile, tectonic plan map, sedimentary facies map and well log sheet to generate 3D tectonic-stratigraphic framework of basin, and also develop the technique to establish spatial information system of real 3D digital basin. Boundary Replacement (B-Rep) model, a kind of GIS data structure, is used to describe the relationship among entities in basin and a set of complete and practical coding methods and principles of modeling are brought forward. On the basis of B-Rep model and these coding methods and principles of modeling, some interpolation methods are introduced. A new method, similar deformation interpolation method, is put forward. After establishment of a basin three-dimensional tectonic-stratigraphic framework, analysis methods of 3D GIS are introduced to analyze the 3D digital basin. It is farther discussed how to use 3D GIS analysis method to realize vector cutting of the 3D digital basin in this paper. It is also discussed how to use three-dimensional dynamic analysis technique to simulate the process of generation, expulsion, migration and accumulation of petroleum. Spatial database technique of 3D GIS is also applied to manage, save and search all kinds of vector data, raster data and attribute data during basin modelling. At the end of paper, it is expatiated how to use 3D WebGIS to publish and share three-dimensional tectonic-stratigraphic framework of basin on the Internet. In short, the B-Rep model, 3D GIS spatial analysis, 3D GIS spatial database and 3D WebGIS are introduced into geosciences in this paper.