| Digital terrain as a way to express the earth's surface rolling is very important in the application of military simulation, geological analysis, virtual geography environment simulation, and the ecological environment. Grid and TIN model are widely used in digital terrain modeling. TIN model is more widely used because it well considers the terrain characteristics. However, people have different demand on the terrain detail degree with different application purpose. And very often, people don't need huge data to construct detailed terrain model. Besides, huge data will make higher demand on computers. So, terrain-simplify technology is proposed to solve the problem.Now there are many methods about TIN model simplification in graphics and geological field. Because of the good fidelity, the Progressive Meshes algorithm in graphics field is widely concerned. Based on ArcGIS Engine, the Progressive Meshes algorithm was implemented with C#.NET, and improved by using Quadric Error Metrics. This dissertation simplifies the terrain with the improved algorithm, evaluate the quality of the Simplified model and studies on the applicability of terrain simplification with mass characteristics using PM algorithm.When analyzing the applicability, this dissertation firstly assesses the quality of simplified terrain model from the aspect of visual judgment, quantitative analysis and application analysis. Then, the dissertation compares the simplified result of PM algorithm with the result of Vertex clustering, Triangle collapse, Quad tree and wavelet analysis.The result of the experiment shows that the TIN simplification using PM algorithm is more effective in general. The PM algorithm well considers the terrain characteristics, but it finds that different assessment methods will get different quality analysis results. |
