如何在matplotlib中设置多边形补丁的边缘颜色

Question

I managed to render a polygon patch onto a matplotlib canvas.

In the code below node_coods is a Nx2 numpy array containing a vertices of polygon.

from matplotlib.patches import Polygon
from matplotlib.collections import PatchCollection

polygon = Polygon(node_coods, closed=True, edgecolor='r')
patches = [polygon]
p = PatchCollection(patches, cmap=mpl.cm.jet, alpha=0.4)
ax.add_collection(p)

At present my plot looks like this, notice it does not have edge color, inspite of passing the argument as given in manual . How do I set the edge color of the polygon patch? I would like to set it to red, (but I'd like to have it tunable to any RGB value later)

Answer 1

Since you do

p = PatchCollection(patches,  alpha=0.4)

per the documentation, edgecolors is default to None , which got override by matplotlib.rcParams default settings, which is transparent. So either do:

p = PatchCollection(patches, edgecolor='r', alpha=0.4)
ax.add_collection(p)

which gives

Or just use add_patch :

polygon = Polygon(node_coods, closed=True, edgecolor='r')
# patches = [polygon]
# p = PatchCollection(patches,  alpha=0.4)

fig, ax = plt.subplots()
ax.add_patch(polygon)

which gives: