Digital Elevation Model(DEM) finds its widely using in the areas of Geography

landscape and regional planning. The abbreviation DEM is used to describe a digital data set which is used to model a topographic surface (a surface representing height data). Since this is impossible

a surface model approximates a continuous surface using a finite number of observations. In its simplest form a vector DEM mimics the raster version by using a regularly spaced set of spot heights to represent the terrain surface. A more advanced

more complex and more common form of vector DEM is the triangulated irregular network (TIN). In vector GIS a TIN is used to create a DEM from either regular or irregular height data. However

some systems have their different request of the data volume under different scale for the influence on the speed of operation and analysis. Besides

cartography generalization of the contour can be realized by the generalization of DEM. So the generalization model on DEM grid data is given in this paper by using the multi band wavelet analysis

and a case study is put forward to give the detail explanation. Meantime

its reliability is described from the point of data volume

profile of the elevation and change of curve surface area.