Colorbar for matplotlib plot_surface command

Question

I changed the mplot3d example code for my application using Paul. The code reads:

from mpl_toolkits.mplot3d import Axes3D import matplotlib.pyplot as plt import numpy as np fig = plt.figure() ax = fig.add_subplot(111, projection='3d') u = np.linspace(0, 2 * np.pi, 100) v = np.linspace(0, np.pi, 100) x = 10 * np.outer(np.cos(u), np.sin(v)) y = 10 * np.outer(np.sin(u), np.sin(v)) z = 10 * np.outer(np.ones(np.size(u)), np.cos(v)) z1 = z * np.cos(0.5*x) N = z1 / z1.max() # normalize 0..1 surf = ax.plot_surface(x, y, z, rstride=1, cstride=1, facecolors=cm.jet(N), linewidth=0, antialiased=False, shade=False) fig.colorbar(surf, shrink=0.5, aspect=5) plt.show() 

This code is great for building a surface. But when I try to add a colorbar to the above chart, I get the following error:

 Traceback (most recent call last): File "<ipython console>", line 1, in <module> File "C:\Python26\lib\site-packages\spyderlib\widgets\externalshell\startup.py", line 122, in runfile execfile(filename, glbs) File "C:\Documents and Settings\mramacha\My Documents\Python\Candela\test.py", line 22, in <module> fig.colorbar(surf, shrink=0.5, aspect=5) File "C:\Python26\lib\site-packages\matplotlib\figure.py", line 1104, in colorbar cb = cbar.Colorbar(cax, mappable, **kw) File "C:\Python26\lib\site-packages\matplotlib\colorbar.py", line 706, in __init__ mappable.autoscale_None() # Ensure mappable.norm.vmin, vmax File "C:\Python26\lib\site-packages\matplotlib\cm.py", line 261, in autoscale_None raise TypeError('You must first set_array for mappable') TypeError: You must first set_array for mappable 

I would be so grateful if anyone could help me.

Prabhu

Answer 1

You can use a proxy object as your array of arrays is not displayed. The displayed transformation simply converts the values ​​of any array to the RGB colors defined in the color palette.

In your case, you want to do this using the z1 array:

 import matplotlib.cm as cm m = cm.ScalarMappable(cmap=cm.jet) m.set_array(z1) plt.colorbar(m)