Abstract:

An algorithm for evaluating the intersection or union area of polygons can be implemented by polygon cllp- ping. The main idea in this paper is using  polygon lists in Weiler-Atherton’s algorithm for polygon clipping. While traversing the list, the algorithm changes direction when it meets the interse ection points, then the poknt-sets of the union of poly- gons can be obtained. On the other hand, if the algorithm starts traversing from an entry point and changes direction when it meets the points of intersection,the point-sets of the overlap can be obtained. Finally, with the two lists we can evalua te their area. The algorithm can handle general polygons including concave polygons and even polygons with holes inside.

Key words: polygon,, area of overlap, area of union, algorithm