Based On The Opengl 3d Terrain Visualization

The terrain is one of the most complex natural scenery, fluctuant and changeable, with a big data quantity. With the deepening research of geography, two-dimensional expression of the geography surface information could not meet people's needs already, so it causes the people to change the way of geographical information expression from two-dimensional to three dimensional. The development of computer graphics, topography and mathematics has afforded a scientific solution to various problems people met in dealing with three-dimensional visualization. The simulation to the realistic terrain could benefit in launching each item related with the natural landscape and raising the working efficiency, so it is significant to research the visualization of three-dimensional terrain.This article has firstly introduced the concept of reality virtualization technology and the visualization of three-dimensional terrain, as well as the critical technology of realizing the visualization of three dimensional terrains.Then it began to make a study of key technologies in building terrain model geometry, and deeply researched the way of using point-by-point insert algorithm to get on Delaunay triangulation. The experiment proves:point by point insertion algorithm can quickly build Delaunay triangular mesh with high-quality, and solve the TIN configuration problems of establishing of geometric model of the terrain in Fuxian Lake Valley.The next is a research of the establishment of a multi-resolution terrain LOD (Level of Details) model, the emphasis of which is how to achieve multi-resolution LOD model with a TIN structure, combining with terrain block management techniques based on QuadTree algorithm and TIN simplification ideas based on VDPM algorithm. The method is:divide the whole terrain into a number of sub-blocks first, and then various sub-blocks were built into TIN to simplify and generate into various detailed levels and store them separately in order to put the rendering into use through quad-tree space index. The adoption of this method needs to address three key issues:the simplification of TIN, the construction of quad-tree and cracks repairing. The results of experiment show that:it could express its features very well with the establishment of the three-dimensional geometric model of Fuxian Lake basin with this method.The last research is the technology route of realizing three-dimensional terrain visualization with the use of OpenGL rendering technique. The result of experiment is: three-dimensional model of Fuxian Lake Basin could be drawn efficiently with the use of OpenGL rendering pipeline made through this experiment, three-dimensional scene roaming was realized, and the terrain of Fuxian Lake basin was vividly recreated.The three-dimensional visualization terrain model made through the experiment has laid the foundation for the establishment of three-dimensional management information system of Fuxian Lake basin. On this basis, various spatial analysis functions ware developed and a number of attributes layers ware established. It will be convenient for the managers of Fuxian Lake basin to get a more intuitive and comprehensive understanding of this area. Additionally, it has provided a more scientific basis for the management and planning to this area.