The 3D Visualization Of Terrain And Terrain Category Based On DEM

3D terrain visualization is the three dimensions terrain modeling by using computer graphics technology, and realistically repetition the real world scenario through the augmented reality technology such as texturing, lighting.3D terrain visualization is one of important research direction of the three-dimensional geographic information system, has important applications in national defense construction, transport planning, game development, and other fields. Real-time rendering 3D terrain is comparatively mature in the PC, how to implement large-scale 3D terrain real-time rendering in the mobile terminal is a new problem. With the rapid popularization of mobile devices and improvement of mobile equipment performance, and new demand based on terrain visualization is put forward, such as 3D-LBS service. Research and application of the mobile platform has become the trend of development.This paper studies the DEM data pretreatment technology, three-dimensional terrain multi-resolution rendering technology and 3D modeling technology of the land-use current map, develops a 3D terrain viewing client, main work of the paper is as follows:Aiming at the problem of low efficiency of terrain rendering, a terrain simplification algorithm based on terrain quad-tree structure is put forward, achieve the effective simplification of grid data and improve the efficiency of drawing.A terrain data organization method based on Out-of-core is put forward. Binding data compression algorithms and terrain simplification algorithm, studies a scheduling method based on pyramid height map, compresses the terrain data to reduce the amount of data which from external memory to memory, keeps the file index as the way access to large files, to quickly access to large files of the local terrain data.The method of constructing three-dimensional model of Land-use current map based on and DEM data is proposed. Implements the 3D visualization of the land-use current map by vector rasterizing technology combined with texture mapping technology, and further puts forward the method of quickly building three-dimensional model of the land-use current map, and the test to get good results.Based on the above technical research results, Combined with the Software engineering technology, The Android 3d terrain visualization software is designed and completed. The test result show that the application rendering is fluent and interactive feel is good.