Customize existing color bar

Question

How to move white portion of diverging color bar towards maximum value or minimum value.

import matplotlib.cm as cm
import matplotlib.pyplot as plt
import matplotlib as mpl
norm = mpl.colors.Normalize(vmin=0,vmax=600)
fig, ax = plt.subplots(figsize=(6, 1))
fig.subplots_adjust(bottom=0.5)
cb1 = mpl.colorbar.ColorbarBase(ax, cmap=cm.PiYG,
                                norm=norm,
                                orientation='horizontal')
cb1.set_label('Some Units')
fig.show()

Answer 1

You have to use the TwoSlopeNorm normalization class

In [5]: import matplotlib.pyplot as plt 
   ...: import matplotlib as mpl 
   ...:  
   ...: norm = mpl.colors.TwoSlopeNorm(vcenter=450, vmin=0, vmax=600) 
   ...: fig, ax = plt.subplots(figsize=(6, 1)) 
   ...: fig.subplots_adjust(bottom=0.5) 
   ...: cb1 = mpl.colorbar.ColorbarBase(ax, cmap=mpl.cm.PiYG, 
   ...:                                 norm=norm, 
   ...:                                 orientation='horizontal') 
   ...: cb1.set_label('Some Units')