Study On Large Scale 3-Dimensional Terrain's Visualizing System

3D terrain has extensive application in many fields, such as city planning, engineering design, environment supervision, disaster forecast, military affairs, games and entertainment. At present, how to realize the visualization of large scale 3D terrain based on great data is the hot topic of research, the following studies have been done around the problem.The structural features of several data model of general digital terrain data have been compared, the dynamic partition and fast reading algorithm based on grid has been proposed, it has proved that this algorithm can solve the modeling problem of large scale 3D terrain.For the dynamic partition and fast reading algorithm of huge data, auto adaptation balance subsystem of terrain data has been designed. The system can adjust the amount of data processed by it automatically, make the system with various functions run steadily and affectively, enhance the compatible property of the system.The mergence of image information in large scale 3D terrain scene has been realized by texture mapping, the mergence of image information in many kinds spacial topics is the basis of special analysis, by the systemAiming at the bad details expressing ability of large scale terrain, the details expressing methods based on image rendering have been introduced, in order to reinforce the details expressing of the terrain.Two modes of observation have been designed: study mode of large terrain scenes and rapid exploring mode in small areas, so the system can not only render large scale scene of terrain, but also observe, measure, compute, analyzing in small areas.The toolkit (Fast Lightened Tool Kit, FLTK) that can be obtained freely has been introduced, and the system based on FLTK and OpenGL has been designed. For good properties in transplantation and compatibility, the system has excellent ability of running in many kinds of operation systems and upgrading to network version.