Discrete logarithmic colorbar in matplotlib

Question

I want to create a pcolormesh plot with a discrete logarithmic colorbar. Some resolution is lost, but the matching between colors and values seems to be easier (at least for me) if the colormap is discrete.

The code snippet below produces a continuous log colormap with the preferred value range. How can I make it discrete? Here I found how to create a discrete linear colormap, but I couldn't extend it to log scale.

plt.pcolormesh(X,Y,Z,norm=mcolors.LogNorm(vmin=0.01, vmax=100.))
plt.colorbar()
fig  = matplotlib.pyplot.gcf()
fig.set_size_inches(4*2.5, 3*2.5)
plt.xlabel("X", horizontalalignment='right', x=1.0)
plt.ylabel("Y", horizontalalignment='right', y=1.0)
plt.tight_layout()

Answer 1

The parameters boundaries and spacing='proportional' in plt.colorbar() do the trick. Using the example given by Talis:

import matplotlib.pyplot as plt
import numpy as np
from matplotlib import colors

X = np.arange(0, 50)
Y = np.arange(0, 50)
Z = np.random.rand(50, 50)*10

bounds = [0.1, 0.2, 0.5, .7, .8, .9, 1, 2, 3, 4, 5, 6, 7, 10]

plt.pcolormesh(X,Y,Z,vmin=min(bounds),vmax=max(bounds),norm=colors.LogNorm(), cmap='RdBu_r')
cbar = plt.colorbar(boundaries=bounds,spacing='proportional')
cbar.set_ticks(bounds)