Point in Polygon

pnpoly.py

# http://geomalgorithms.com/a03-_inclusion.html
# https://wrf.ecse.rpi.edu//Research/Short_Notes/pnpoly.html
# https://ru.wikibooks.org/wiki/Реализации_алгоритмов/Задача_о_принадлежности_точки_многоугольнику
# https://github.com/gregvw/pnpoly

def inPolygon(x, y, xp, yp):
   c=0
   for i in range(len(xp)):
       if (((yp[i]<=y and y<yp[i-1]) or (yp[i-1]<=y and y<yp[i])) and \
           (x > (xp[i-1] - xp[i]) * (y - yp[i]) / (yp[i-1] - yp[i]) + xp[i])): c = 1 - c    
   return c

print( inPolygon(100, 0, (-100, 100, 100, -100), (100, 100, -100, -100)))