点、多边形拓扑关系与多边形顺、逆判断优化算法

点与多边形拓扑关系判断是空间拓扑分析的重要内容之一,基于以往算法不可靠和过于复杂的缺点,本文提出了面积判断法,很好地解决了上述问题,且对于含有孤岛的多边形仍然有效。矢量多边形坐标存储顺、逆时针的判断是数据验证、数据转换必不可少的一项,但对于此种算法少有提及,为此本文提出了外围判断法,可以较为简单地完成此项任务,填补了此类算法的空白。

An Optimized Algorithm to Determine Topo-relation Between Point and Polygon and Clockwise or Anti-clockwise in Polygon

Analysis of topological relation between point and polygon is an important component of topological analysis.Because the old algorithm is too uncertain and complicate to use,this paper proposes area-judgement method to solve those problems.That algorthm is suitable to polygon with isolated islands too.It is necessary to determine whether a polygon's coordinates are stored in clockwise or anti-clockwise order for data check and data transformation.But there only a small quality of such algorithm is shown.Therefore,this paper proposes the periphery judgement method and such analysis will be finished easily.It is a supplement of such algorithm.