分布式流域水文模型的DEM数据处理

分布式流域水文模型从DEM数据中提取河流,由于地图数据的比例尺、DEM网格的分辨率等原因,生成的河流可能与真实的河流不重合,流域内的径流可能汇集不到出口断面,必须对DEM数据进行处理。目前GIS软件中常用的处理方式是将河流经过的网格高程普遍降低,这种方法还不够理想。理想的DEM数据处理方法应满足以下原则:修改后生成的河流与真实的河流重合,流域内的径流能够汇入河道到达流域出口断面;DEM数据中网格的高程来自实测地图,最能代表网格的高程,只是由于对网格高程的插值滤掉了一些地形细节,因此高程修改的网格数目应达到最小。基于这个原则,提出DEM数据修改方法,平滑掉河流经过的凸起网格并且填充流域内的洼地,修改最少的网格高程,使由DEM数据生成的河流能够与真实的河流重合,达到模拟真实的径流流动路径的目的。

DEM Data Processing for Distributed Hydrological Model

In distributed hydrological model studying,due to precision and resolution of DEM data,the rivers generated from DEM data are often different with the real rivers,because the runoff can not reach the outlet of valley,so that the DEM data need to be modified.At present,reduced elevation of gird that river pass through is the method adopted by most of GIS software,and there are some distance from this method to the ideal.The ideal method of DEM data modifying should obey the principle:after modified DEM data generated rivers are same with the real river,the runoff can flow to outlet of valley;DEM data is generated from real measured space data,is most representative elevation of grids,just because in the interpolating of elevation some important detail is filtered,so it is best to minimize number of elevation modified DEM grid.The method of DEM data process mentioned in this paper is based above principle,raising part of river and lose pit of basin are smoothed,so generated rivers are same with the real river,runoff can flow to outlet of valley.