3d Gis In Terrain Visualization Technology And Realization

With the deeper research of GIS, the description of geographical information has expended to 3 dimensional out of 2 dimensional. Terrain is a vital natural entity, is the fundamental information in GIS. Expressing the terrain truely and real-time has significant meaning to spatial cognization. In recent years, the achievements if the computer graphic, topography, mathematics will show the possibility to solve this problem.This paper covers the fundamental concept of 3D terrain modeling, techniques to build terrain model, and construct the multi-resolution model in real-time render, based on all of these, give an terrain visualization example.Firstly, method to modeling terrain is discussed, including RSG(Regular Square Grid) and TIN(Triangulated Irregular Network). Then as far as the TIN model concerned, several algorithms were analyzed, describe the specialties of them. Next the technique of build the multi-resolution terrain model was researched, especially the simplicity of the terrain model. The newest development in LOD was introduced, then, gave a multi-resolution modeling algorithm based on TIN, and accomplished a 3D terrain visualization system by OpenGL.