Distance between point and a line (from two points)

python numpy vector scipy point
user1185675 picture user1185675 · Oct 3, 2016 · Viewed 42.4k times · Source

I'm using Python+Numpy (can maybe also use Scipy) and have three 2D points 

(P1, P2, P3);

I am trying to get the distance from P3 perpendicular to a line drawn between P1 and P2. Let P1=(x1,y1), P2=(x2,y2) and P3=(x3,y3)

In vector notation this would be pretty easy, but I'm fairly new to python/numpy and can't get anythng that works (or even close).

Any tips appreciated, thanks!

Answer

DotPi picture DotPi · Oct 3, 2016

Try using the norm function from numpy.linalg

d = norm(np.cross(p2-p1, p1-p3))/norm(p2-p1)

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