How can I get the (x,y) values of the line that is plotted by a contour plot?

Question

Is there an easy way to get the (x,y) values of a contour line that was plotted like this:

import matplotlib.pyplot as plt
x = [1,2,3,4]
y = [1,2,3,4]
m = [[15,14,13,12],[14,12,10,8],[13,10,7,4],[12,8,4,0]]
cs = plt.contour(x,y,m, [9.5])
plt.show()

Answer 1

Look at the collections property of the returned ContourSet. In particular the get_paths() method of the first collection returns paired points making up each line segment.

cs.collections[0].get_paths()

To get a NumPy array of the coordinates, use the Path.vertices attribute.

p1 = cs.collections[0].get_paths()[0]  # grab the 1st path
coor_p1 = p1.vertices