Color matplotlib plot_surface command with surface gradient

Question

I would like to convert surf command from MATLAB to plot_surface command in matplotlib.

The challenge I am facing is when using cmap function in plot_surface command to color the surface with gradient.

Here is the matlab script

% Matlab Commands
x = -5:.25:5; y = x
[x,y] = meshgrid(x);
R = sqrt(x.^2 + y.^2);
Z = sin(R)
surf(x,y,Z,gradient(Z))

The figure from such a command can be found here. (http://www.mathworks.com/help/techdoc/visualize/f0-18164.html#f0-46458)

Here is the python scipt When using python and matplotlib to create a similar function I am unable to color the surface with a gradient.

# Python-matplotlib Commands
from mpl_toolkits.mplot3d import Axes3D
from matplotlib import cm
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure()
ax = fig.gca(projection='3d')
X = np.arange(-5, 5, 0.25)
Y = np.arange(-5, 5, 0.25)
X, Y = np.meshgrid(X, Y)
R = np.sqrt(X**2 + Y**2)
Z = np.sin(R)
surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=gradient(Z), linewidth=0, antialiased=False)
plt.show()

I get the following error message:

Traceback (most recent call last):
  File "", line 1, in 
  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	mp.py", line 13, in 
    surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=gradient(Z), linewidth=0, antialiased=False)
  File "C:\Python26\lib\site-packages\mpl_toolkits\mplot3d\axes3d.py", line 729, in plot_surface
    polyc = art3d.Poly3DCollection(polys, *args, **kwargs)
  File "C:\Python26\lib\site-packages\mpl_toolkits\mplot3d\art3d.py", line 344, in __init__
    PolyCollection.__init__(self, verts, *args, **kwargs)
  File "C:\Python26\lib\site-packages\matplotlib\collections.py", line 570, in __init__
    Collection.__init__(self,**kwargs)
  File "C:\Python26\lib\site-packages\matplotlib\collections.py", line 86, in __init__
    cm.ScalarMappable.__init__(self, norm, cmap)
  File "C:\Python26\lib\site-packages\matplotlib\cm.py", line 155, in __init__
    self.cmap = get_cmap(cmap)
  File "C:\Python26\lib\site-packages\matplotlib\cm.py", line 126, in get_cmap
    if name in cmap_d:
TypeError: unhashable type: 'list'

Any inputs would be helpful.

Praboo

Color matplotlib plot_surface command with surface gradient

1 Answers