基于轮廓不同的DEM对宁波市姚江流域平原河网的提取研究

目的]针对目前基于DEM提取平原河网所遇到的困境,采用新的视角提取平原河网,为完善水系自动化提取方法研究提供依据。方法]采用Acr Hydro Tools和SWAT工具在轮廓不同的DEM下,对宁波姚江流域进行河网提取和流域确定。再以提取后的流域总面积与河流总长度为定量分析的主要指标,用相对误差公式、河网套合差公式和Visual Similarity Duplicate Image Finder软件进行综合评价与误差分析。结果]在真实河网辅助下,Acr Hydro Tools与SWAT均是在规整型DEM基础上的提取效果很差。在临近型DEM上所提取的河网、流域和流域总出口与实际相符且精度、相似度都很高。结论]用Acr Hydro Tools和SWAT两种工具提取流域水系都是可取的,但SWAT更加便捷;不同轮廓的DEM以及其是否与流域总出口相切会极大地影响河网提取的质量。

Extraction Study of Plain River Network in Yaojiang River Basin of Ningbo City Based on DEM of Different Contour

Objective] Concerning the shortage in the extraction of plain river network based on DEM, we adopted a new method to extract plain river network and to provide basis for automatic drainage extraction method.Methods] Using Acr Hydro Tools and SWAT, the river network of Yaojiang river basin in Ningbo City was extracted in DEMs with different contour. The extracted total area of the basin and total length of rivers were used as the main index of quantitative analysis. Relative error formula, matching error formula of river network and Visual Similarity Duplicate Image Finder software were used for comprehensive evaluation and error analysis.Results] With the help of the real river network, the extracted results based on Neat DEM by Acr Hydro Tools and SWAT were very bad. However, the extracted river network, basin and total basin export based on Adjacent DEM were consistent with the actual, and the precision and similarity were also high.Conclusion] Extracting basin and river network with Acr Hydro Tools and SWAT are all desirable, but the SWAT is more convenient. The quality of river network extraction is dependent on DEM contour and also dependent on whether the DEM is tangent with the total basin export or not.