python3射线法判断点是否在多边形内

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#!/usr/bin/python3.4# -*- coding:utf-8 -*-  def isPointinPolygon(point, rangelist):  #[[0,0],[1,1],[0,1],[0,0]] [1,0.8]    # 判断是否在外包矩形内,如果不在,直接返回false    lnglist = []    latlist = []    for i in range(len(rangelist)-1):        lnglist.append(rangelist[i][0])        latlist.append(rangelist[i][1])    print(lnglist, latlist)    maxlng = max(lnglist)    minlng = min(lnglist)    maxlat = max(latlist)    minlat = min(latlist)    print(maxlng, minlng, maxlat, minlat)    if (point[0] > maxlng or point[0] < minlng or        point[1] > maxlat or point[1] < minlat):        return False    count = 0    point1 = rangelist[0]    for i in range(1, len(rangelist)):        point2 = rangelist[i]        # 点与多边形顶点重合        if (point[0] == point1[0] and point[1] == point1[1]) or (point[0] == point2[0] and point[1] == point2[1]):            print("在顶点上")            return False        # 判断线段两端点是否在射线两侧 不在肯定不相交 射线(-∞,lat)(lng,lat)        if (point1[1] < point[1] and point2[1] >= point[1]) or (point1[1] >= point[1] and point2[1] < point[1]):            # 求线段与射线交点 再和lat比较            point12lng = point2[0] - (point2[1] - point[1]) * (point2[0] - point1[0])/(point2[1] - point1[1])            print(point12lng)            # 点在多边形边上            if (point12lng == point[0]):                print("点在多边形边上")                return False            if (point12lng < point[0]):                count +=1        point1 = point2    print(count)    if count%2 == 0:        return False    else:        return True  if __name__ == '__main__':    print(isPointinPolygon([0.8,0.8], [[0,0],[1,1],[0,1],[0,0]]))  

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