Function for finding the area of a polygon in a 2D co-ordinate system.
Python, 8 lines
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Copy to clipboard1 2 3 4 5 6 7 8 | def poly_area2D(poly):
total = 0.0
N = len(poly)
for i in range(N):
v1 = poly[i]
v2 = poly[(i+1) % N]
total += v1[0]*v2[1] - v1[1]*v2[0]
return abs(total/2)
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This function implements Green's theorem, also known as the shoelace theorem or the surveyors' theorem, which is the 2D case of the more general Stokes' theorem.
