[Matplotlib-users] Single colorbar for two overlaid contourf plots

[zetah <ot...@hu...>]

Hi,

in this example:

========================================
import numpy as np
import matplotlib.pyplot as plt

arr = np.random.random((10, 10))

plt.contourf(arr, 10)
plt.contourf(arr, 10, cmap='coolwarm', levels=np.arange(0, 1, .2), alpha=.5)
plt.colorbar()
plt.show()
========================================

colorbar is representing last contour. 

I want to make colorbar that will match actual plot, which is combination of two contours obviously. I tried also something like:

========================================
import numpy as np
import matplotlib.pyplot as plt

arr = np.random.random((10, 10))

fig = plt.figure()
ax = fig.add_subplot(111)

cax = ax.contourf(arr, 10)
cb = fig.colorbar(cax)
cax = ax.contourf(arr, 10, cmap='coolwarm', levels=np.arange(0, 1, .2), alpha=.5)
cb.update_bruteforce(cax)    # tried also: cb.update_normal(cax)

plt.show()
========================================

but it didn't get me there. Is there some easy way to do this?

Thanks