基于ASTER GDEM的延河流域水系提取及面积高程积分研究

Study on Drainage Network Extraction and Hypsometric Integral in Yanhe Watershed Based on ASTER GDEM

以延河流域为例,基于ASTER GDEM,采用图解建模方法提取河网进行面积高程积分分析。结果表明,汇流阈值越大,河道数目、河道总长和河网密度均呈现持续下降趋势;当汇流阈值为6200时,河网密度为0.28,趋于平稳;不同汇流阈值产生的河网形态各有差异,阈值越大,生成河网越稀疏,反之越密集。面积高程积分HI分析结果表明,延河大多区域处于发育壮年期,处于发育幼年期、壮年期和老年期面积分别约占总面积的0.4%、98.2%和1.4%。

Based on ASTER GDEM, graphical modeling method was used to extract the river network and analyzed the hypsometric integral in the Yanhe basin. The results showed that when the threshold increasing, the number of channels, gullies length and gully density all was a trend of decline. Gully density levels was off with the value of 0.28 when the threshold value was equal or greater than 6200. Different threshold could produce the different river networks, the bigger the threshold value, the sparser the river network. The result of HI implied that the Yanhe was mostly in the evaluation process of mature stage. The area percent of geomorphologic evaluation process in infancy, mature and old stage was 0.4 %, 98.2 % and 1.4% respectively.