matplotlib hist2d colormap for null pixels

Question

I found the general approach to set the null pixels to white is to use a lognorm colormap.

Is there a way to use a linear colormap but still set null pixels to white?

Thanks!

Answer 1

In new versions of matplotlib you can simply use cmin = 1, i.e.

plt.hist2d(x,y,cmin = 1)

will set all bins with fewer than one count to nan, i.e. nonvisible. If your background is white (default) then these bins will appear white. But they will change wil the background.

Answer 2

You can use '.set_under':

import matplotlib.pyplot as plt

my_cmap = plt.cm.jet
my_cmap.set_under('w',1)
...
plt.hist2d( ..., cmap = my_cmap)

This sets all values under 1 (i.e. the lowest count) to 'w' (=white).