Extraction Of Terrain Features Line With Contour Data And Research On Topographical Modeling

With the development of Geographic Information System, Digital ElevationModel (DEM) is widely used in Geographic Information System (GIS), it has already totally become an important component of the Geographic Information System.At first this paper introduces a new method which is named as the concentric circles cutting method of drawing terrain characteristic line on the basis of contour vector data, and has made the program design and realized to this method.Subsequently the method of funding DEM model and the way to express DEM are discussed, two kinds of main forms of expression to DEM ?Triangulated Irregular Network model and Regular Square Grid model are compared with and analyzed; On the basis of analyzing the algorithm of constructing TIN, Based on the grow method of triangular network, the algorithms design and realization are carried out about the course of constructing TIN; To improve topographical modeling precision , it is discussed that features of terrain are taken into account in the construction course of Triangulated Irregular Network(TIN) model. It is provided that a special processing method to the terrain characteristic line in the modeling course. It is proposed that the realizing thought and steps about the constrained Delaunay triangulation which is based on the incremental-point producing algorithm, and the algorithm has also been designed.