Automatic Polygonization Algorithm on Parallel and Graph Model

The polygon construction is the emphasis and difficulty for constructing the topological relationship of spatial data. Many scholars continuous study and innovate for the algorithm. The traditional computational process mainly involves three steps in algorithms: (1) Determining the relationship between adjacent arcs. (2) Searching polygons. (3) Determining the topological relationship between arcs and polygons. With the increase of the number of data and the need to improve the automatization, speed and complexity of algorithm, the serial algorithm has become more and more difficult in polygon construction and is often more time consuming. The algorithm of polygon construction is meeting challenge with the development of computer technology. When processing the large-scale linear data, an efficient strategy to reduce the time of complex operations in algorithm has not been proposed in spatial data field. We propose a novel algorithm to construct polygons automatically in the parallel environment base on the new IT technology. The key of the algorithm is paralleling the more time consuming operation (search, sort. etc.) and improving the speed of polygon construction. According to the characteristics of directed rings in graph model, we construct topological polygons. The experimental results on multicore computers show that the algorithm is efficient parallel performance for polygon construction.