First what version of mpl are you using? if it is recent this colour word
already exists, I asked about this a couple months ago and i should point you
first to the example in the svn it does a checkerboard, but i cannot remember
the exact name. Although i know it plots a checkerboard effect on one of the
example plots.
The way that color keyword is set up, it is dedsigned to take a color word or
rgba tuple , (Reinier will know this better than me), however if you want to
just assign colors based on a colour map you can take you color array and
reshape the same way the plot surface command does then use surf.set_array()
here is a snippet of the code I use to do this I am pretty sure it won’t run
the way it is right now but the idea is buried in there
note that regmap xyz and costmapz are all the same size and are nxm matrices
costmapout is a 2x(m.n) if i can do the math correctly
from mpl_toolkits.mplot3d import Axes3D
from matplotlib import cm
import numpy as np
#--------------------------------------------------
ax = Axes3D(fig)
scale= 3
surf = ax.plot_surface(regMAPx ,regMAPy,-regMAPz ,
rstride=scale,cstride=scale, cmap=cm.jet, linewidth=.250 )
# to reshape the cost map to match grid used in plot surf
rows, cols = costMAPz.shape
costmapout = []
for rs in np.arange(0, rows-1, scale):
for cs in np.arange(0, cols-1, scale):
costmapout.append(costMAPz[rs][cs])
costmapout=np.array(costmapout)
surf.set_array(costmapout)
## do your show plot stuff here!!
Mike Alger
From: Pablo Angulo [mailto:pablo.ang...@uam.es]
Sent: June-11-10 7:04 AM
To: matplotlib-users@lists.sourceforge.net
Subject: [Matplotlib-users] color in plot3d
Hello!
I wonder if there is a way to make 3d plots specifying arbitrary colors,
instead of having the color be a function of the height. I was able to achieve
this making minimal changes to the plot_surface method of Axes3D, adding as an
optional keyword argument a function cfun which specifies the color (it
specifies a real number that is mapped into a color by the color map cmap). But
is there a standard way?
Regard
Pablo Angulo
from matplotlib.colors import Normalize, colorConverter
def plot_surface(self, X, Y, Z, *args, **kwargs):
'''
Create a surface plot.
By default it will be colored in shades of a solid color,
but it also supports color mapping by supplying the *cmap*
argument.
========== ================================================
Argument Description
========== ================================================
*X*, *Y*, Data values as numpy.arrays
*Z*
*rstride* Array row stride (step size)
*cstride* Array column stride (step size)
*color* Color of the surface patches
*cmap* A colormap for the surface patches.
*cfun* The function giving the color
========== ================================================
'''
had_data = self.has_data()
rows, cols = Z.shape
tX, tY, tZ = np.transpose(X), np.transpose(Y), np.transpose(Z)
rstride = kwargs.pop('rstride', 10)
cstride = kwargs.pop('cstride', 10)
color = kwargs.pop('color', 'b')
color = np.array(colorConverter.to_rgba(color))
cmap = kwargs.get('cmap', None)
cfun = kwargs.pop('cfun', None)
polys = []
normals = []
avgz = []
if not cfun:
cfun = lambda p:p[2]
for rs in np.arange(0, rows-1, rstride):
for cs in np.arange(0, cols-1, cstride):
ps = []
corners = []
for a, ta in [(X, tX), (Y, tY), (Z, tZ)]:
ztop = a[rs][cs:min(cols, cs+cstride+1)]
zleft = ta[min(cols-1, cs+cstride)][rs:min(rows, rs+rstride+1)]
zbase = a[min(rows-1, rs+rstride)][cs:min(cols, cs+cstride+1):]
zbase = zbase[::-1]
zright = ta[cs][rs:min(rows, rs+rstride+1):]
zright = zright[::-1]
corners.append([ztop[0], ztop[-1], zbase[0], zbase[-1]])
z = np.concatenate((ztop, zleft, zbase, zright))
ps.append(z)
# The construction leaves the array with duplicate points, which
# are removed here.
ps = zip(*ps)
lastp = np.array([])
ps2 = []
avgzsum = 0.0
for p in ps:
if p != lastp:
ps2.append(p)
lastp = p
avgzsum += cfun(p)
polys.append(ps2)
avgz.append(avgzsum / len(ps2))
v1 = np.array(ps2[0]) - np.array(ps2[1])
v2 = np.array(ps2[2]) - np.array(ps2[0])
normals.append(np.cross(v1, v2))
polyc = art3d.Poly3DCollection(polys, *args, **kwargs)
if cmap is not None:
polyc.set_array(np.array(avgz))
polyc.set_linewidth(0)
else:
colors = self._shade_colors(color, normals)
polyc.set_facecolors(colors)
self.add_collection(polyc)
self.auto_scale_xyz(X, Y, Z, had_data)
return polyc
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