Vectorization algorithm for raster data based on boundary-searching

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 simplerightmostdirection 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.