geospatialpython/PiP_Edge.py at master · ucespff/geospatialpython · GitHub

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# Improved point in polygon test which includes edge

# and vertex points

def point_in_poly(x,y,poly):

# check if point is a vertex

if (x,y) in poly: return "IN"

# check if point is on a boundary

for i in range(len(poly)):

p1 = None

p2 = None

if i==0:

p1 = poly[0]

p2 = poly[1]

else:

p1 = poly[i-1]

p2 = poly[i]

if p1[1] == p2[1] and p1[1] == y and x > min(p1[0], p2[0]) and x < max(p1[0], p2[0]):

return "IN"

n = len(poly)

inside = False

p1x,p1y = poly[0]

for i in range(n+1):

p2x,p2y = poly[i % n]

if y > min(p1y,p2y):

if y <= max(p1y,p2y):

if x <= max(p1x,p2x):

if p1y != p2y:

xints = (y-p1y)*(p2x-p1x)/(p2y-p1y)+p1x

if p1x == p2x or x <= xints:

inside = not inside

p1x,p1y = p2x,p2y

if inside: return "IN"

else: return "OUT"

# Test a vertex for inclusion

poligono = [(-33.416032,-70.593016), (-33.415370,-70.589604),

(-33.417340,-70.589046), (-33.417949,-70.592351),

(-33.416032,-70.593016)]

lat= -33.416032

lon= -70.593016

print point_in_poly(lat, lon, poligono)

# test a boundary point for inclusion

poly2 = [(1,1), (5,1), (5,5), (1,5), (1,1)]

x = 3

y = 1

print point_in_poly(x, y, poly2)

geospatialpython/PiP_Edge.py at master · ucespff/geospatialpython · GitHub

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