Research And Application Of Three Dimension Terrain Visualization

3D terrain visualization is a research subject on the simplification, display and simulation of Digital Terrain Model(DTM). It is extensively used in Geographic Information Systems(GIS), Virtual Reality(VR),Game Engine and some other fields. The two key issues of 3D terrain visualization are how to simplify terrain model and how to store terrain data. In simplification of terrain, multi-resolution terrain algorithm is undoubtedly the most powerful solution. And the partition loading algorithm offers a good solution to the second problem. This thesis discusses these two crucial research issues,and explores new methods and techniques.The thesis first studies the basic theories and methods of the terrain model, focusing on multi-resolution terrain model. This paper surveys existing multi-resolution modeling techniques, and comprehensively summarize the previous work. Based on those work, a series of optimization and a new method to increase the rendering speed of terrain is proposed which greatly improve the rendering speed and consume less memory resource.Then,for large-scale terrain loading problem, in this paper, a new large-scale terrain partition loading algorithm is proposed. The algorithm can effectively solve large-scale terrain rendering issues.It also greatly reduces the memory consumption of rendering algorithm. And the algorithm can be used with the Level of Detail (LOD) algorithm to achieve high rendering speed and low memory consumption.In this paper, two kinds of large-scale terrain block-loading algorithms are presented to adapt to different application environment demands. One is based on single height map file, the other is based on multi-files.The first algorithm is simple, but it need lots of memory. The second algorithm is flexible and adaptable,it also can implement unlimited maps.Finally, a complete real-time terrain roaming system is implemented, which is based on the previous algorithm.