局部曲面正切曲率与流线曲率的水流路径算法

在局部特殊地形如细窄的沟渠等地带,水流方向可能是惟一的,即当前点的水应全部流入下游惟一的格网点,此时若采用多流向算法不仅会导致水流方向产生较大误差,而且可能影响区域汇水面积的精确计算。为解决此问题,本文提出了一种水流路径算法,该算法通过以各格网点为中心建立3×3窗口范围内的局部趋势面,利用该点在局部趋势面中的正切曲率和流线曲率选取合适的单流向或多流向算法来确定并计算该点的水流流向及流量分配比例。最后通过实例证明了该方法在水流累积量计算中的良好效果,并在一定程度上为格网DEM沟谷段和分水线段的提取奠定了基础。

Flow paths algorithm based on tangential curvature and flow-path curvature of partial surface

The flow direction is sole and single in some local special terrain locations such as narrow ditches and so on,that is,all water of the current point should flow into the only grid point which locates on the lower places of current point.At this time,using the multiple flow direction algorithm may lead to some greater errors in the calculation of the flow direction,which may also affect the accurate calculation of the regional catchment area.To solve this problem,a flow path algorithm was proposed in the paper,a piece of partial surface was established through 9 grid points which act as the neighbors of the center grid point and locate in the range of the 3×3 window,and through the tangential curvature and the flow-path curvature of the current center grid point of the partial surface,the single flow direction algorithm or the multiple flow direction algorithm would be determined which calculate the flow direction of the current grid point and its distribution ratio of water flow.Finally,the good results using this method in the accumulation of the water were proved,and this method could lay the basis for the extraction of the channel links and the divide links in the grid DEM to some extent.