#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Date : 2018-10-07 15:49:37
# @Author : Sheldon (thisisscret@qq.com)
# @Blog : 谢耳朵的派森笔记
# @Link : https://www.cnblogs.com/shld/
# @Version : 0.0.1
def isinpolygon(point,vertex_lst:list, contain_boundary=True):
#检测点是否位于区域外接矩形内
lngaxis, lataxis = zip(*vertex_lst)
minlng, maxlng = min(lngaxis),max(lngaxis)
minlat, maxlat = min(lataxis),max(lataxis)
lng, lat = point
if contain_boundary:
isin = (minlng<=lng<=maxlng) & (minlat<=lat<=maxlat)
else:
isin = (minlng<lng<maxlng) & (minlat<lat<maxlat)
return isin
def isintersect(poi,spoi,epoi):
#输入：判断点，边起点，边终点，都是[lng,lat]格式数组
#射线为向东的纬线
#可能存在的bug，当区域横跨本初子午线或180度经线的时候可能有问题
lng, lat = poi
slng, slat = spoi
elng, elat = epoi
if poi == spoi:
#print("在顶点上")
return None
if slat==elat: #排除与射线平行、重合，线段首尾端点重合的情况
return False
if slat>lat and elat>lat: #线段在射线上边
return False
if slat<lat and elat<lat: #线段在射线下边
return False
if slat==lat and elat>lat: #交点为下端点，对应spoint
return False
if elat==lat and slat>lat: #交点为下端点，对应epoint
return False
if slng<lng and elat<lat: #线段在射线左边
return False
#求交点
xseg=elng-(elng-slng)*(elat-lat)/(elat-slat)
if xseg == lng:
#print("点在多边形的边上")
return None
if xseg<lng: #交点在射线起点的左侧
return False
return True #排除上述情况之后
def isin_multipolygon(poi,vertex_lst, contain_boundary=True):
# 判断是否在外包矩形内，如果不在，直接返回false
if not isinpolygon(poi, vertex_lst, contain_boundary):
return False
sinsc = 0
for spoi, epoi in zip(vertex_lst[:-1],vertex_lst[1::]):
intersect = isintersect(poi, spoi, epoi)
if intersect is None:
return (False, True)[contain_boundary]
elif intersect:
sinsc+=1
return sinsc%2==1
if __name__ == '__main__':
vertex_lst = [[0,0],[1,1],[1,2],[0,2],[0,0]]
poi = [0.82,0.75]
print(isin_multipolygon(poi,vertex_lst, contain_boundary=True))
