基于数字高程模型的流域轮廓自动提取方法与应用

流域轮廓提取通常指提取流域的边界和河网.对这两个流域要素的提取是进行精确的流域水文模拟的基础.由于传统的基于地形图的手工方法效率低,精度差,因此研究了如何使用Arc-GIS软件进行流域轮廓的自动提取.研究所使用的数据是栅格格式的数字高程模型,根据水流方向的最速下降原则(D8算法),对原数据按下列顺序进行处理:数据预处理-水流方向网格图层生成-水流累积网格图层生成-河道分段-子流域辨识-子流域边界矢量化,最后获得矢量化的河网和子流域边界.在此过程中,通过对河道分段的阈值的选取,可以获得不同密度的河网和不同尺寸的子流域.将该方法应用于长江的一条支流-清江流域,结果显示该方法是可行和有效的.

River Basin Delineation Based on Digital Elevation Model

River basin delineation refers to the extraction of the basin boundaries and channel networks.The delineation of these two river basin elements is the basis for accurate hydrologic modeling of river basins.As the traditional way of delineation being of low-efficiency and poor-accuracy,the study carried out in this paper investigated how to perform an automatic delineation based on ArcGIS software.The source data used is the Digital Elevation Model(DEM) in raster format,based on the premise that water flows along the path of steepest descent,following procedure is followed to obtain vectorized river channel networks and subbasin boundaries: data pre-processing-flow direction calculation-flow accumulation calculation-stream segmentation-subbasin identification-subbasin boundary vectorization.In this process,the density of channel network and the size of the subbasins are controlled by selecting different threshold in stream segmentation.The methodology were applied to one of the tributaries of the Changjiang River,the results shows that the methodology is feasible and effective.