Research Of Digital Elevation Model Generation And Visualization Based On TIN

Digital Elevation Model (DEM) is one of the important parts of the geographic information systems.This thesis mainly focuses on the algorithm of the convex hull with the discrete points, the algorithm for the Delaunay triangulation with the discrete points, the algorithm of the Constrained Delaunay triangulation,and the terrain 3D visualization,surrounding the DEM data model based on the TIN.At the aspect of the algorithm of Convex hull,this thesis presents an algorithm for generating convex hull of discrete points based on axis. First sort the discrete points by x-axis, and then construct an axis using the first point and the last point. Whether a point is involved in the upper half convex hull or the lower half convex hull construction is determined by its position. The thought of the algorithm is simple, easy to program, good robustness and high operating efficiency.At the aspect of the discrete points Delaunay Triangulation, this thesis,achives the Delaunay Triangulation based on the "convex hull" going forward.At the aspect of the constrained Delaunay triangulations.First,uses the discrete points and the control points of the constrained edges to constitute a Delaunay triangulation,and then embedded the constrained edges to the Delaunay triangulation.At the aspent of terrain 3D visualization, this thesis generated the three dimensional visualization of the DEM data using 3D visualization technology provided by the OpenGL...