Three-dimensional Modeling And Visualization Of Geographic Information System Technology Research,

Geographic Information System (GIS) has constrained to the two-dimension for a long time. The two-dimension GIS has its own fault which is hard to overcome. That is, it can only manager the information over the plane constructed by X-Y axes but the Z axes. It is in essence a system based on the abstract symbol, so it can't show the actual feeling of nature.With the development of GIS application, the people demand the three-dimension GIS urgently. Compared to the two-dimension GIS, the three-dimension GIS can give people the more true feeling of the external world. It displays the geographic space phenomenon by solid sculpt technology. So the research on three-dimension visualization system of geographic information has highly value.This paper studies the three-dimension modeling, spatial analysis, visualization of the three-dimension visualization system of geographic information and related technologies. The three-dimension modeling is to construct the three-dimension solid surface by plentiful discrete data point, and to save the data point information and the relation between points. In this thesis, the author discusses the process of constructing triangulated irregular network with discrete point and improves the algorithm of constructing Delaunay network. In order to realize the real-time display of the three-dimension scene, the author analyses the complicated terrain model simplification and multiresolution representation, and brings forward a view-dependent dynamic multiresolution model and its related algorithm. Spatial analysis is an important characteristic and one of the primary targets of GIS, so the author researches the analysis of the basic topographic factor, visibility, contour, flood submerging. In the end, the author discusses the process of visualization, and researches the technology of hidden-line, illumination, texture mapping and animation. The three-dimension spatial data visualization can provide more direct and actual object for the management and decision-making. The research on this subject has considerable value for implementing the three-dimension visualization system of geographic information.