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获取与真实状况吻合的河网是建立流域水文模型及进行水文研究的重要前提,而基于航天飞机雷达地形(SRTM)数字高程模型(DEM)栅格影像的水文分析所获得的河网可能与实际河网有一定程度的误差,在实际应用中,需要对原始DEM数据进行核查并校正.以甬江流域作为研究案例,采用该流域的2D标准河网矢量剖面分析排水路径的DEM高程值,并依据排水路径中河网的下游低于上游的原则,识别逆向坡度节点.应用编辑的Arcpy程序对河网逆向坡度节点重新计算,得到符合物理意义的3D河网矢量,并将其值反演至原始DEM栅格数据.实验表明,基于上述处理后的DEM数据所提取的河网趋近于实际河网.
Obtaining river networks consistent with real conditions is an important precondition for the establishment of hydrological models and hydrological studies in river basins. The river network obtained from hydrological analysis based on the raster image of SRTM digital elevation model (DEM) The river network has a certain degree of error, and in the practical application, the original DEM data needs to be verified and corrected.With the Yongjiang river basin as a case study, the 2D standard river network vector profile of the river basin is used to analyze the DEM elevation value of the drainage path, Identify the reverse grade nodes by using the principle of downstream lower reaches of the river in the drainage channel to identify the reverse grade nodes.Apply the edited Arcpy program to recalculate the reverse grade nodes of the river network to get the 3D river network vectors that meet the physical meaning and invert the values to the original DEM grid data.Experiments show that the river network extracted based on the above-processed DEM data approaches the actual river network.