基于均值变点分析的三峡库区河网提取研究

Extraction of drainage network in Three Gorge reservoir area based on mean change point method

均值变点是最常见最直观的一种类型,它以平均值为分析对象,通过计算整个样本数据的方差(S)与分段样本的统计量(Si)之差来确定变点,变点的存在会使S和Si的差距增大。本文以SRTM DEM数据作为基本的地形数据,借助Arc Hydro Tools扩展模块,研究基于地表径流漫流模型的数字河网提取方法,采用均值变点分析法确定提取河网的阈值,并对结果进行分析。经对比发现,提取的主干河网与1∶250 000地形图主干上吻合较好,次流上更具真实性,提取结果可以用于各种地形分析。

Mean change point is the most common and intuitive type, it chooses the mean value as the research object and determines the change point by calculating the difference between S and Si. The existence of change point would increase the gap between S and Si. The paper took the SRTM DEM data as the basic terrain data, studied the method of how to extract drainage network based on ground water overflow model, determined the threshold of drainage extraction relying on the mean change-point analysis method and an- alyzed the extraction results. By contrast, the authors found that the main drainage network competed well with the 1 ： 250 000 topo- zraDhic mad but there were some slight differences in the tributary. The result could be used in all kinds of terrain analysis.