基于GIS的河道贴体网格自动生成算法研究

利用地理信息系统(GIS)基于空间位置信息的技术特点,对河道贴体网格的自动化生成算法进行了研究。基于GIS矢量线的节点间空间位置关系,对任意位置上的河道流向进行了较高精度的数值表达,进而实现了河道断面的自动剖分;设计出一系列算法,解决了网格生成过程中可能出现的交叉、拧绕等问题,从而保证了剖分网格对河道区域平面分布的自适应性特征;基于数字高程模型(DEM)高程插值,对河道区域地表模型进行重建与分析,生成得到的河道贴体网格。经验证,该算法具有较好的贴体性质和较高的运算效率。

Research on a GIS-based automatic generation algorithm of body-fitted meshes adaptive to river terrain

A new method based on geographic information system (GIS) is presented to generate body-fitted meshes automatically. First, a principle is put forward to express the variable flow direction numerically in close approximation, which is based upon the spatial relationship between nodes of the river centerline; then, sections vertical to the flow direction are partitioned throughout the river, and a smoothening method is worked out to prevent overlapping sections from coming into being. A uniform relationship between the sampling direction and the flow direction at anywhere should be guaranteed in order to eliminate "wresting" phenomena in output results and the "right-hand" rule is applied here. And then, an elevation-based interpolation algorithm is designed to reconstruct the landscape model of the river, which is in the form of the output body-fitted meshes. At last, results and tests of the algorithm in pictures and tables are also provided, which proves the algorithm to be well body-fitted and efficient.