Axes3d plot_surface not supporting masked arrays?

[maxnoe]

Consider this code:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.colors as colors
from matplotlib import cm
from mpl_toolkits.mplot3d import Axes3D

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection='3d')

x, y = np.meshgrid(np.linspace(-1, 1), np.linspace(-1, 1))
z = x**2 + y**2

z[10:20, 10:20] = 0.0

masked_array = np.ma.masked_equal(z, 0.0)
palette = cm.gray
palette.set_over('g', 1.0)
palette.set_under('b', 1.0)
palette.set_bad('r', 1.0)

ax.plot_surface(x,y,masked_array,
    rstride=1,
    cstride=1,
    cmap=palette,
    vmin=-1,
    vmax=1,
    )
plt.show()

The area set to zero should be red, but it isn't. It works on a 2d axis using pcolormesh.

[jklymak]

As discussed in #18114 I think the mask should apply to the z data, in which case there is no elevation to plot so no colour would be shown.

If you want an elevation to be plotted, don't mask, and do any of the masking in the colormap, and pass colormapped data facecolor=C, where C = norm(maskedZ)