利用DEM提取河网时集水面积阈值的确定

Determination of River Drainage Area Threshold for Extraction of Drainage Network by DEM

在O′callaghan和Mark方法中引入了集水面积阈值的概念,对于同一流域利用不同集水面积阈值得到不同的河网。提出了利用河源密度(或河网密度)与集水面积阈值的关系确定理想的集水面积阈值,当河源密度(或河网密度)趋于稳定时的面积阈值为所需要的。将该方法应用于沿渡河流域得到的河网与地形图中的“蓝线”河网拟合较好。提出的方法排除了在选取集水面积阈值时的主观随意性。

The algorithm for delineation of a river drainage network proposed by O′callaghan and Mark is widely used. A drainage area threshold is used to produce a continuous network, so that different network is obtained by varying drainage area threshold. A method in which the relation between source density (or drainage density) and the threshold is used to produce an ideal drainage network is proposed. The drainage area threshold with stabilized source density (or drainage density) is wanted. The method is used in Yanduhe watershed and a good result is obtained. The proposed approach removes the subjective decision on the choice of drainage area threshold.