One rasterization approach algorithm for high performance map overlay

It is a critical technique in GIS about how to implement map overlay with high performance. To avoid the disadvantages of computational geometry algorithm approach, an optimal algorithm based on rasterization is proposed in this paper, which adopts approach of rasterization of vector polygons with run length encoded scan line, map overlay on the basis of raster representation and vectorization of binary raster data with improved boundary tracing method. Experiments show the significant performance and efficiency improvements of the proposed algorithm, which is one promising solution for the map overlay function of on-line map service system taking the approach of pre-rendered raster tiles with predefined map scales.