数字河网提取时集水面积阈值的确定

Determination of catchment area threshold for extraction of digital river-network

为得到一种切实可行的阈值选取方法,使提取的数字河网有利于后期的水文分析,以古蔺河流域为例,应用ArcGIS水文分析模块,基于30 m分辨率的DEM基本地形数据,采用"阈值—河网密度"的方法做出其关系图,利用"阈值—河源密度"的方法进行检验。结果表明,这种方法是可行的,避免了在阈值选取方面的盲目性,同时也可以应用到其他流域的数字河网提取。

In order to get a practical and feasible method for selecting the threshold, and then make the extracted fiver-network be fevorable to the late hydrological analysis, its relationship diagram is made by taking Gulinhe River Watershed as a study case with the method of ＂threshold fiver-network density＂ through the application of ArcGIS hydrological analysis module based on basic DEM terrain data with the resolution of 30 m, thereafter, it is verified with the method of ＂threshold river-network den- sity＂ as well. The result shows that this method is feasible, thus not only the blindness in the aspect of the threshold selection is avoided, but it can be also applied to the extraction of the river-networks in the other river basins.