Research on a GIS-based automatic generation algorithm of body-fitted meshes adaptive to river terrain
JIANG Zhi-jun~1,LI De-ren~1,WANG Wei~1, LI Lan~2, YI Hua-rong~1emote Sensing,Wuhan University,Wuhan 430079, China;2.School of Hydraulic and Electric Engineering, Wuhan University, Wuhan 430072, China)
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.