CODEWITHSUNDEEP
pythonmatplotlib
Zach G
Zach G

Reputation: 645

How to white out a matplotlib pyplot image outside of rectangle borders

The plot below is a matplotlib contourf figure, with matplotlib.pyplot Rectangles overlayed on top to make a grid.

What would be the best way to white out the contourf plot outside of the Rectangle borders? Contourf plot with Rectangle grid overlay

Upvotes: 2

Views: 924

Answers (2)

ImportanceOfBeingErnest
ImportanceOfBeingErnest

Reputation: 339300

You can use a pcolormesh on top of the contour plot such that it hides the area below it.

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-120.,120.,13)
X,Y = np.meshgrid(x,x)

Z = X*np.sqrt(np.abs(Y))*np.exp(-(X**2+Y**2)/3000.)
Xf = X.flatten()
Yf = Y.flatten()
Zf = Z.flatten()
cond = Xf**2+Yf**2 < 105**2
Xf = Xf[cond]
Yf = Yf[cond]
Zf = Zf[cond]

cond2 = X**2+Y**2 < 105**2
mask = np.zeros_like(X)
mask = np.ma.masked_array(mask,mask=cond2)

fig, ax = plt.subplots()
ax.tricontourf(Xf,Yf,Zf, levels=np.linspace(Z.min(), Z.max(), 10))

dx=np.diff(X[0,:])[0]; dy=np.diff(Y[:,0])[0]
ax.pcolormesh(X,Y,mask, zorder=2, cmap="gray", vmin=-1)
ax.pcolormesh(X-dx,Y-dy,mask, zorder=2, cmap="gray", vmin=-1)
ax.pcolormesh(X,Y-dy,mask, zorder=2, cmap="gray", vmin=-1)
ax.pcolormesh(X-dx,Y,mask, zorder=2, cmap="gray", vmin=-1)

ax.scatter(Xf,Yf, c="k", s=5, zorder=3)
plt.show()

enter image description here

Upvotes: 1

Padix Key
Padix Key

Reputation: 970

This is kind of a hack, but I think you could draw filled white rectangles in the size of your black border rectangles in order to hide the contour plot at these positions.

Upvotes: 0

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