A Self-intersecting Polygon Processing Algorithm in the Vectorization of Classified Raster Data

The data points which cause self-intersecting polygon in the vectorization of classified raster data are firstly analyzed and defined as the diagonal node.An general concept of self-intersecting polygon is given.Further,an algorithm is presented to process the self-intersecting polygon.Tests with real data demonstrate that the algorithm is very effective to handle all diagonal nodes to 2-connected direction points,and there is no self-intersecting polygon in the vector results.A comparative test between the algorithm and the method used in the ENVI software is made to prove that the self-intersecting polygons in the result of ENVI do not appear in the result obtained by the method present in this paper.Therefore the method in this paper is better than that of ENVI.