Research And Realization On 3D GIS Visualization System Based On OpenGL

With the development of deeper research on GIS, the description of geographical information has been extended to 3D dimensional out of 2D dimensional. Thus, 3D GIS modeling at present is becoming the key technology of the new GIS system. The Terrain is a vital natural entity, and has the feature of complicated and various characteristics, e.g. huge data amount. The application of terrain has very significant position in GIS application, and its expression has profound meaning for accurate spatial cognition. In this paper, it introduces the basic concept of 3D terrain modeling, and deeply researches the construction of terrain model, and generation of multi-resolution model in real-time drawing process, based on the achievement above, to develop a terrain 3D visualization prototype system example.The paper Firstly discusses the three methods to modeling, including RSG(Regular Square Grid) and TIN(Triangulated Irregular Network). Then as far as the TIN model concerned, we analyze the construction algorithms, and describe the specialties of them, and use the point-wise inserting algorithm to construct it. Next the techniques of building the multi-resolution terrain model was researched, especially the simplicity of the terrain model, and we distribute a multi-resolution model generating algorithm based on TIN, and realize the above algorithm in the VC++6.0 developing environment. In the end, based on what we research, we accomplish a terrain 3D visualization system based on OpenGL.The research of this paper has significant meaning in theory and practise. In theory, the research from constructing terrain, data model, data structure point of view; in practise, this research is to realize the foundation of digital earth and 3D GIS, and the crucial point of 3D visualization map; in military application it has a bright future; in the meantime, it is the best means of expressing for tourism region...