A Novel Algorithm for Union between Complex Polygons

The union operation, one of the spatial analysis operations, plays an important role in the capability of GIS software. At present, many algorithms for this operation have been put forward; however, most of them have limitation on handling general polygons. In this paper, introducing the trapezoidal-mesh data structure and the split-and-merge technique, an efficient union algorithm has been ad-dressed, which is suitable for general polygons. The trapezoidal data structure is simple and the operations based on it are easily to be implemented. Being applied in GIS platform software, this algorithm has been proved of high efficiency and occupying less memory.