数字河网自动提取是流域水系网络结构研究、分布式流域水文模拟中的重要内容。它不仅可以帮助我们迅速计算流域水系结构特征指数，而且作为分布式流域水文模型的输入信息，为分布式河道汇流演算提供了依据。详细研究了一种由brecht和Martz提出的比较系统的数字河道网络提取和结构特征描述方法。采用该方法来从汉江流域上游的旬河流域的数字高程模型中进行数字河网提取、河道分级和河段节点编码。结果表明，所提取的数字河网和实际情况相符，而且河段节点编码非常科学，在此基础上所建立的河道网络拓扑关系结构非常有助于分布式汇流计算。

The automated extraction of the digital river network from digital elevation models is very important for the researches on both the river network structure analysis and the distributed watershed hydrological modeling. The automated digital river network extraction can not only help us quickly calculate the indices reflecting the river network characteristics, but also provide a basis for distributed flow routing. This paper introduces in? detail the automated method of digital river network extraction and analysis proposed by Garbrecht and Martz. This method has been applied to the Xunhe catchment in the upstream Hanjiang Basin for the digital river network extraction, the stream ordering and the channel section node indexing. It is found that the extracted digital river network is very close to the true situation. Besides, the topological relationship established on the basis of channel section node indices is very helpful to the distributed river flow routing.