基于地图代数的数字地表流线模拟研究

降雨在地表上随地形流动自然形成沟谷线、汇流区、分水岭等流域形态,研究地表流水线的数字模拟对数字流域水文分析具有重要意义.提出数字地表流线模型的概念,只考虑地形因素,利用等高线图建立一个能获得区域内每滴雨水沿地表流动的轨迹模型.并运用地图代数的距离变换对等高线及所在空间进行全方位的距离度量,研究了数字地表流线模型的建立方法.实验表明,该模型利用距离变换信息而不是高程计算流向,可避免DEM高程误差对流向、流线的影响,且不需要在DEM上进行复杂的洼地、平地的识别与处理.该模型对原始数据要求不高,能有效应用于沟谷线的自动提取、汇流区自动分割和分水线网络的自动提取.

Digital simulation of flow paths on the earth' s surface based on map algebra

Rainfalls flow along the hypsography of the earth's surface,and valley elements such as the valley lines,catchment areas and naturally.Formed watersheds the research on the digital simulation of flow paths on the earth's surface is important for the digital watershed hydrological analysis.This paper puts forward the concept of the digital flow paths model by which we can get the flow path of any raindrop on the earth's surface.The contour lines and spaces are measured by the distance transformation of map algebra,and a method of building the digital flow paths model with the contour maps is advanced in the paper.The experiment result shows that the calculation of flow directions and flow paths can avoid the effect of the DEM elevation errors since the flow direction is calculated with distance transformation instead of D8 algorithm.Compared with the existing methods of the digital hydrological analysis,the method excludes the complex step of identifying and treating the depressions or flats in DEM.The model takes contour maps as original data and it can be availably applied in the extraction of valley lines,the delineation of catchment areas and the generation of watersheds.