python3射线法判断点是否在多边形内

# -*- coding: UTF-8 -*-

def isInsidePolygon(pt, poly):
    c = False
    i = -1
    l = len(poly)
    j = l - 1
    while i < l - 1:
        i += 1
        print(i, poly[i], j, poly[j])
        if ((poly[i][0] <= pt[0] and pt[0] < poly[j][0]) or (
                poly[j][0] <= pt[0] and pt[0] < poly[i][0])):
            if (pt[1] < (poly[j][1] - poly[i][1]) * (pt[0] - poly[i][0]) / (
                poly[j][0] - poly[i][0]) + poly[i][1]):
                c = not c
        j = i
    return c

if __name__ == '__main__':
    abc = [[1,1],[1,4],[3,7],[4,4],[4,1]]
    print(isInsidePolygon([2,5], abc))

第二种方法：

# -*- 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]]))