基于通视性原理的等高线化简算法研究

A Novel of Contour Line Simplification Algorithm Base on Visibility

等高线自动综合历来是制图综合领域的重点和难点。目前已存在的等高线化简方法主要是一种几何上的逼近,由于综合处理后的等高线难以保持原有的形态特征,因此为了更好地进行等高线化简,首次提出了一种基于最大通视条件的新的等高线化简方法。该方法首先利用最大通视性原理划分等高线化简区域,并在每个划分的区域范围内,对曲线段进行弯曲嵌套层次分析和等级划分;然后在此基础上根据曲线段弯曲的等级和预先设定的阈值进行弯曲取舍。实验证明,该方法在控制自相交、特征点保持等方面均明显优于其他化简方法,化简后的形态保持,更符合等高线的综合要求。

It is important but difficult to generalize contour lines in cartographic generalization domain all along, and thegraphic simplification of which is also a necessary difficulty. At present, existent simplification method of contour lines is mainly a geometrical approach, whose results after generalization process can hardly keep the primary shape characteristics. Based on analysis of area dividing and bend nesting of curve by the furthest visibility condition, a new generalization method of contour lines is proposed firstly. The experiment results show that the method is better than Douglas-Peucker algorithmson eliminating self-intersection, keeping character points, and can keep the shape after simplification better.