线要素多尺度表达的一种新方法

本文依据多比例尺条件下矢量数据的绘制原理,提出了多尺度线化简与线选取方法。多尺度线化简算法依比例尺将空间坐标转换为像素坐标,根据像素坐标删除曲线中重合点与共线点,综合后的曲线与原始曲线在各比例尺下绘制结果相同;多尺度线选取算法利用仿射变换结果快速计算线要素之间的连通关系,然后渐进删除长度小于阈值的悬线与孤立弧段,保持了线要素的连通性。对不同类型数据的实验验证了本文算法的有效性和可行性。

A new multi-scale representation approach for line features

According to the multi-scale representation principles of vector data,the paper presented a continuous line simplification algorithm and a continuous line selection algorithm.The line simplification algorithm first transformed the geo-coordinates to pixel-coordinates according to map scales,and then removed coincident pixels as well as collinear pixels on a same line.Therefore,the rendering result of the simplified data was equal to that of the original data.The line selection algorithm calculated the connectivity relationship between lines effectively in terms of pixel-coordinates,and then progressively removed suspension lines as well as isolated lines whose length is within threshold.Experimental results on different types of data demonstrated the availability and feasibility of the approach.