Research Of Terrain Visualization & Railway Information Query In GIS

Terrain visualization, which is put forward with the development of GIS can be applied in many fields. The technology of terrain visualization can contribute to the realization of "Digital Earth".The thesis mainly discusses some aspects of terrain visualization, as follows:Firstly, we make a discussion on terrain data model and its interpolation,representation methods, and then sum up several terrain generation techniques: based on real terrain datasets, data fitting methods, fractal geometry methods and intergrated methods, at the same time, terrain simplication techniques are discussed,which can be described as three stages: discrete LOD, continuous LOD and multiresolution model.Secondly, TIN(Triangulated Irregular Network)can be used better to represent terrain than RSG (Regular Square Grid) in many circumstances.The paper mainly discusses the incremental interpolation algorithm.Then, fractal technique can be used in the generation of terrain, the paper describes fractal theory and analyzes fractal methods of terrain generation. An example of fractal terrain implemented by "midpoint displacement" is provided.Last, an information query system based on the railway is built after we analyze railway modeling and database technique. Correlative techniques about the system are discussed.