关键词: 通视性, 视域, 矢量化, 局部最优, 规则格网

Abstract: An improved algorithm of inter-visiblity based on local optimum detection and elevation constraint is proposed.Firstly，the basic algorithm of inter-visiblity of two 3D points is introduced.Secondly，the definition of the local optimum monotonous zone is given，and the improved algorithm of inter-visibility based on local optimum monotonous zone and elevation constraint is so proposed by analyzing the relationship between the direction of the LOS and the position of shelding point.The implementation of the improved algorithm is introduced.Since there is only an optimum detection executed to the elevation points，and only a relatively small part of points will execute the entire calculation of inter-visibility，the improved algorithm，compared with the basic algorithm，gains a faster convergence rate.Finally，the improved algorithm is verified by the simulation program，and further more，a simulation of viewshed analysis and vectorization based on the proposed algorithm is implemented.

Key words: inter-visibility, viewshed, vectorization, local optimum, Regular Square Grids（RSG）