多尺度小波分析用于DEM网格数据综合

数字高程模型(DEM)虽已广泛应用于地学、景观以及区域规划等工作，然而在不同尺度下，不同的系统对其数据量的要求是不同的，且数据量将影响系统运行及分析的速度；其次等高线的制图综合也可直接通过数字高程模型数据的综合来实现，为了加快DEM数据综合的速度和保持综合前后DEM数据特征一致性，提出了一种采用小波多尺度分析的方法来进行DEM网格数据综合的方案，并给出了数字高程模型网格数据的综合基本模型。同时对综合以后的可靠性分别从数据量、断面图和曲面面积变化等方面进行了分析。具体实例说明，将多尺度小波分析用于DEM网格数据综合是有效的。

Generalization of DEM Grid Data Based on Multi band Wavelet Analysis

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.