一种误差可控的地图边界线的等距线计算方法

在边境地区无线电台站审查、协调需要较高精度地理数据的背景下，提出了一种基于距离场的地图边界线的等距线计算方法。该方法使用规则栅格点构建距离场，通过对误差来源的分析，得到了用栅格点间距表示的误差上界。实际计算时，只需设定一个允许的最大误差值，即可自动完成对指定边界线的计算，得到多边形表示的所需精度的等距线。实验表明基于距离场的方法是可行的并且具有可控的精度，计算的等距线已应用到边境台站的技术审查中。

Approach for offset curves computation from boundaries on map with bounded error

This paper presents an approach for offset curves computation based on distance fields from boundaries on the map for the requirement of accurate geographic data for radio station audition and coordination in national border areas. The distance fileds are constructed from regular grids. An upper bound of error on offset curve related to the step of the grids is given by analysis of error resource. The computation can be carried out automatically with an maximum permissible error. Then the offset curves composed of point sequence on specified precision are obtained. The proposed algorithm has been implemented and tested with a segment of boundary. The results show that it is feasible and accurate. The offset curves have been implemented for national border areas station audition.