Research And Implementation Of Terrain Model Simplification Algorithm Based On Triangulated Irregular Network

As one of "4D" products, Digital Elevation Model has been widely used in Surveying and Mapping, the fields of Remote Sensing, Agriculture, Forestry Planning, Urban rules, Civil and Hydraulic Engineering, Geo-science analysis and other fields. The main three representation of digital elevation model are contour model, triangular mesh model and irregular network model, among those the triangulated irregular network model is better in visualization of terrain. Terrain modeling structure due to the Delaunay triangulation network(hereinafter referred to as D-TIN). In response to this demand point by point insertion algorithm has better flexibility, but its low efficiency.In this thesis, the main research and contents are as follows:(1)In terms of generating Delaunay triangulation, based on the incremental insertion algorithm, Improved convex hull algorithm, to establish the initial inclusion shell, discrete points of the original multi-stage adaptive grid block, and index relationships, and optimize the insertion sequence of discrete points. In establishing the initial containment shell algorithm, proposed the more perfect use of Hao Jianqiang's divided establish positive and negative convex hull; In locating the points, introduction of fusion location algorithm, these improvements make Delaunay triangulation more efficient.(2)In the terrain model simplification, in-depth study of traditional mesh simplification algorithm. Improved the traditional algorithm in the following areas of deficiency: Algorithm-based PM,To determine the new vertex positions to improve and optimize the process boundary vertices and edges, eliminating the progressive mesh ambiguity, while adding the second error of into the weight which based on the curvature of the curve. The improved algorithm effectively maintain the physical characteristics of the grid model, ensuring the correct mesh topology relations, improved quality mesh simplification.(3)In this thesis, for the improved simplification and simulation algorithms of the terrain model, analyze and verify its effectiveness, efficiency.