【Python】地図上の座標が範囲内にあるかを判定する

Python を使って、地図上のある座標が、４つの座標の中に含まれるかどうかを判定したい。

www.dev-dev.net

↓こちらのサイトを参考にしました。

sak12.blogspot.com

#!/usr/bin/env python
#-*- coding:utf-8 -*-
import numpy as np
def main():
n = 1
x = np.ndarray(n, dtype=float)
y = np.ndarray(n, dtype=float)
inside = np.ndarray(n, dtype=bool)
x = [135.4978645]
y = [34.7062076]
inside[:] = False
x1, y1 = [], []
x1.append(135.496926)
y1.append(34.7065168)
x1.append(135.497527)
y1.append(34.7033239)
x1.append(135.4998448)
y1.append(34.7040295)
x1.append(135.498965)
y1.append(34.7067814)
# check the points inside the polygon
for i, (sx, sy) in enumerate(zip(x, y)):
print("i = " + str(i))
print("x = " + str(x))
print("y = " + str(y))
print("sx = " + str(sx))
print("sy = " + str(sy))
inside[i] = inpolygon(sx, sy, x1, y1)
# True or False
print(inside[i])
def inpolygon(sx, sy, x, y):
'''
    x[:], y[:]: polygon
    sx, sy: point
    '''
np = len(x)
inside = False
for i1 in range(np):
i2 = (i1 + 1) % np
if min(x[i1], x[i2]) < sx < max(x[i1], x[i2]):
# a = (y[i2]-y[i1])/(x[i2]-x[i1])
# b = y[i1] - a*x[i1]
# dy = a*sx+b - sy
# if dy >= 0:
if (y[i1] + (y[i2] - y[i1]) / (x[i2] - x[i1]) * (sx - x[i1]) - sy) > 0:
inside = not inside
return inside
if __name__ == "__main__":
main()