Study Of Geography Information System Data Model

This thesis puts forwards a new object-oriented 3D GIS data model, and studies corresponding 3D visualization technology, corresponding spatial analysis technology and spatial query technology on the basis of GIS data model.This thesis brings forwards a new object-oriented city 3D GIS data model by using UML(Unified Modeling Language) on the basis of the analysis of current object-oriented 3D GIS data model studies. The 3D GIS data model is divided into three parts: the base package, the application package and the combination package. The base package including point class, line class, area class, volume class, complex object class and relation class, is the base of the application package and the combination package. The application package includes digital stereo model, level model, digital surface model, digital terrain model, cross-section model, building model, annularity model, field model and CSG(Constructive Solid Geometry). The application package expresses 3D spatial object by exerting some method on base of the base package. The combination package sets up the relations of spatial objects by using some methods as classing, generalizing, combining, clustering, on the base of two forenamed packages. This thesis has also proposed a new modeling method of 3D city GIS landscape. First the photos of building are photographed with a digital cameral. Then digital photographs are calibrated to acquire the image texture of 3D geometric models. Finally a new 3D city GIS model with real image texture is built with VC++6.0 and OpenGL databases. On the base of object-oriented 3D GIS data model and 3D visualization technology, this thesis puts forward a spatial data mining system on GIS and puts up simple spatial analysis according current data mining study. The flow of spatial data mining system is as follow: after user presents some problems, spatial data mining module spring core of spatial data mining to extract useful knowledge from spatial database, then grant discovered knowledge to user.