#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Date : 2018-10-07 15:49:37
# @Author : Sheldon (thisisscret@qq.com)
# @Blog : 謝耳朵的派森筆記
# @Link : https://www.cnblogs.com/shld/
# @Version : 0.0.1

def isinpolygon(point,vertex_lst:list, contain_boundary=True):
 #檢測點(diǎn)是否位于區(qū)域外接矩形內(nèi)
 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):
 #輸入：判斷點(diǎn)，邊起點(diǎn)，邊終點(diǎn)，都是[lng,lat]格式數(shù)組
 #射線為向東的緯線
 #可能存在的bug，當(dāng)區(qū)域橫跨本初子午線或180度經(jīng)線的時(shí)候可能有問題
 lng, lat = poi
 slng, slat = spoi
 elng, elat = epoi
 if poi == spoi:
  #print("在頂點(diǎn)上")
  return None
 if slat==elat: #排除與射線平行、重合，線段首尾端點(diǎn)重合的情況
  return False
 if slat>lat and elat>lat: #線段在射線上邊
  return False
 if slat<lat and elat<lat: #線段在射線下邊
  return False
 if slat==lat and elat>lat: #交點(diǎn)為下端點(diǎn)，對應(yīng)spoint
  return False
 if elat==lat and slat>lat: #交點(diǎn)為下端點(diǎn)，對應(yīng)epoint
  return False
 if slng<lng and elat<lat: #線段在射線左邊
  return False
 #求交點(diǎn)
 xseg=elng-(elng-slng)*(elat-lat)/(elat-slat)
 if xseg == lng:
  #print("點(diǎn)在多邊形的邊上")
  return None
 if xseg<lng: #交點(diǎn)在射線起點(diǎn)的左側(cè)
  return False
 return True #排除上述情況之后

def isin_multipolygon(poi,vertex_lst, contain_boundary=True): 
 # 判斷是否在外包矩形內(nèi)，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))