基于栅格数字高程模型DEM的河网提取及实现

从数字高程模型(DigitalElevationModels)DEM直接提取河网及相关流域信息,是分布式水文模型开发与应用的基础。本文基于D8(eightflowdirectionmatrix)处理方法,开发出一套DEM凹陷区域识别与处理、河网自动生成与流域划分软件。在新疆天山,应用本软件在100m×100m精度的DEM数据上生成的河网与全国1 25万的数字河流对比验证,吻合较好。此外,在美国联邦地质调查局(USGS)的HYDRO1k全球1km精度的DEM数据源基础上,所提取生成的长江流域河网,与1 100万的数字长江主要河道对比,差别不大。结果表明,所开发软件能够很好地自动生成流域水系,可为进一步开发分布式水文模型提供技术基础。

Deriving drainage networks and catchment boundaries from Grid Digital Elevation Model

Digital data of the position and characteristics of river networks and catchment are important for the construction of physically based distributed hydrological model, in which a detailed definition of a catchments internal drainage structure is required. By applying the eight flow direction matrix ( D8) approach, a software on extracting drainage networks from raster Digital Elevat ion Models ( DEM) has been developed. Based on the software, a drainage network from 1×1 DEM with 100m resolution was derived for Tianshan region in Xingjiang and it compares well with the digital blue river with 1/250000 resolution in this region. Besides, a drainage network of the Yangtze River basin, whose drainage area is over 1800000 km2 , has been extracted, based on the free digital elevation data of 1-km resolution and USGS HYDROlk data set, Using the Pfafstetter scheme, the river network has been separated into the main river course and tributaries. Good visual consistence was obtained to compare the extracted river networks with digital actual river, as well as the inter-basins boundary and drainage area. The results imply that the proposed software is apt to automatically extract drainage networks from grid DEM with reliable resolution.