Setting matplotlib colorbar range

Question

I would like to set the matplotlib colorbar range. Here's what I have so far:

import numpy as np import matplotlib.pyplot as plt x = np.arange(20) y = np.arange(20) data = x[:-1,None]+y[None,:-1]  fig = plt.gcf() ax = fig.add_subplot(111)  X,Y = np.meshgrid(x,y) quadmesh = ax.pcolormesh(X,Y,data) plt.colorbar(quadmesh)  #RuntimeError: You must first define an image, eg with imshow #plt.clim(vmin=0,vmax=15)    #AttributeError: 'AxesSubplot' object has no attribute 'clim' #ax.clim(vmin=0,vmax=15)   #AttributeError: 'AxesSubplot' object has no attribute 'set_clim' #ax.set_clim(vmin=0,vmax=15)   plt.show() 

How do I set the colorbar limits here?

Answer 1

Arg. It's always the last thing you try:

quadmesh.set_clim(vmin=0, vmax=15) 

works.

Answer 2

Matplotlib 1.3.1 - It looks like the colorbar ticks are only drawn when the colorbar is instanced. Changing the colorbar limits (set_clim) does not cause the ticks to be re-drawn.

The solution I found was to re-instance the colorbar in the same axes entry as the original colorbar. In this case, axes[1] was the original colorbar. Added a new instance of the colorbar with this designated with the cax= (child axes) kwarg.

           # Reset the Z-axis limits            print "resetting Z-axis plot limits", self.zmin, self.zmax            self.cbar = self.fig.colorbar(CS1, cax=self.fig.axes[1]) # added            self.cbar.set_clim(self.zmin, self.zmax)            self.cbar.draw_all()