一种基于边界搜索的栅格矢量化算法

Vectorization algorithm for raster data based on boundary-searching

栅格数据的矢量化是GIS领域重要的研究内容。针对栅格数据矢量化准确率低和效率低等问题,该文提出了一种基于边界搜索的矢量化算法,通过对栅格图像的一次遍历,提取结点和中间点,生成弧段,构建多边形;并在构建多边形中,提出了一种简单易行的最右侧方向判断方法,综合运用最小外接矩形和射线法判定逆时针多边形的归属。实验表明,该文提出的矢量化算法能够较准确矢量化复杂的栅格图像,具有较好的效率,可为多值栅格图像快速矢量化及相关研究提供借鉴。

Vectorization is of great importance to spatial analysis and image processing in GIS.A vectorization algorithm based on boundary-searching was developed in this paper.The raster map was traversed for one time and the coordinates and the linking information of the boundary points were obtained.Then,arcs and polygons were constructed with the linking information.It proposed a simple＂rightmost＂direction method to trace polygon boundaries,which improved the method of determining the polygon each inner ring belongs to by using the minimum bounding rectangle and ray method.Experiments showed that the vectorization method could process complex raster data correctly and efficiently.The result would provide some reference for the vectorization of multi-valued raster images.