By means of GIS method, the digital elevation model(DEM)is established, the subcatchment boundaries are studied.
利用 GIS 方法建立了数字高程模型（DEM），研究了子汇水面积的边界。
2
By means of GIS method, the digital elevation model(DEM)is established, the flow direction, flow accumulation, subcatchment boundaries and stream network spatial distribution are studied.