Delaunay triangulation based on nesting island with holes

Islands are composed by closed arcs without intersection with each other. The relationship between islands can be either nesting or mutually independent. Through the analysis on nesting relationship among the islands, the arcs compositing islands are divided into four basal types, moreover, every type is provided an algorithm for calculation. The inner of islands is automatically identified according to the types of arc segments and then a triangulation algorithm with constrained condition was carried out. According to previous method, complex triangulations are structured. The efficiency of compiling relative programs to verify algorithm is mainly determined by the efficiency of formatting delaunay of triangulation.