Generation And Application Of DEM

Simulation of digital terrain is a course that directs to topography, the consequence of modeling generally is named a digital terrain elevation mode. By mean of such digital expression, 3D feature of real world can be actual reproduction. In recent years, because of development of GIS, DEM as an important result of digital terrain simulation has become a primary content of national spatial data infrastructure, and also achieve economics of scale in production as digital space frame.At present, Grid and TIN are amphi-primary data structure of DEM. Grid express terrain by an equal space of topographic point's height in horizontal and vertical direction. The plane coordinate of Grid point is implicit in row and column. Owing to the superiority of Grid in storage,management and convenient for use, it has became a kind of extensively used data structure. But the shortcoming is incapable of expression of terrain well and truly, while the size of cell is not change. It cannot representatively terrain detail section. TIN can joint discrete points in a certain manner, and generate optional triangle cover whole region even each other underlay. Establish discrete points of compartment spatial relation actually. TIN can be adaptable regular array of data and irregular distribution of data, at the same time well enough that interpolate for production square grid data, it can be able to best take into account morphologic characteristics point and line, it can express complicated terrain surface.It is a key target for computer-aided cartography that interpolated contour from DEM, also is principal application for DEM. Contour can actual express topography and height low wave of terrain. It is an important element of map. Toward Grid data we can avail the information of data that storage in the data structure, so we can trace contour direct. But it is usually discrete point, therefore we construct triangulation net first, then realize auto-trace contour based on it.This paper studies DEM produce and based on DEM auto-trace contour mean. The major content of this paper include: (1) DEM data acquisition as well as staple data structure; (2)TIN construct method and topological auto-establish; (3)different kind of mathematical model for establishing Grid, to realize that discrete data production Grid; (4)trace contour base on Grid and TIN as well as the method of curve slick algorithm.