利用不同数字高程模型的水系提取对比分析

Comparison of Drainage Network Extractions from Two DEMs

水系提取是研究流域水文的基础,基于单流向算法(D8),选取SRTM DEM与ASTER GDEM两种高程数据提取水系,试验得出SRTM的汇流累积量阈值为10 000(栅格),GDEM的汇流累积量阈值设定为90 000(栅格).分别用两种DEM合适阈值提取的水系结果对比分析,并利用实际河网和遥感影像进行验证,结果表明:利用SRTM DEM提取大范围水系的精度和效率较高.相对于平坦地区,地形起伏大的地区精度更高.可用于指导水系提取时数据源的选取.

Extracting of drainage network is the foundation of watershed hydrology studies. The paper compared two river network extractions by SRTM DEM with a flow accumulation threshold of 10 000 grids and ASTER GDEM with a flow accumulation threshold of 90 000 grids,using the D8 single flow direction algorithm,and verified the drainage network extraction with real river and remote sensing image. The results show that widearea drainage network extraction from SRTM DEM has higher precision and efficiency. It is more accurate in undulating areas than in flat areas and can be used for choice of data sources river network extractions.