Abstract: Proposed a new approach of vectorization for raster data in order to extract the vector region information from raster data efficiently,which traverses the raster data sequentially using a scan-line method,organizes the Pixel Directed Edge using the linked list technique to constitute region boundaries dynamically,and determines the ownership of isolated island using the hidden ray method.This approach could convert a raster spot into a vector region directly by making use of the spatial information implied in raster data,such as the arrangement of pixels and the feature of Pixel Directed Edge we defined.It could obtain the complete vector information of a region by traversing the raster data only once without any intermediate data and some other operations like constructing topological relationship of polygons.Our method turns to be a one-step vectorization solution for raster spots.Experimental results show that the approach is efficient and easy to implement.