关键词: 等距线, 缓冲区, 距离场, 地理信息系统

Abstract: 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.

Key words: offset curves, buffer zone, distance field, Geographic Information System（GIS）