[Matplotlib-users] converting GMT color palettes to pylab colormaps

[Michael H. <mh...@us...>]

Does anyone here have any experience converting GMT color palettes  
into pylab colormaps?  I took a stab at it, and the results are not  
really what I expected.

GMT, for the unfamiliar, is a scientific plotting/mapping package  
that I'm doing my best to rid myself of.  If you've never heard of  
it, then you can probably ignore this message.

Here's my attempt at bringing in a GMT color palette:

#!/usr/bin/python

from pylab import *

#GMT color palette - Colors are specified by a RGB triplet with each  
value in the range
#0-255.  The palette below specifies that a data value between 1 and  
2 will be assigned a color
#linearly interpreted between the colors (255,255,255) and  
(191,204,255).

# 0       255     255     255     1       255     255     255
# 1       255     255     255     2       191     204     255
# 2       191     204     255     3       160     230     255
# 3       160     230     255     4       128     255     255
# 4       128     255     255     5       122     255     147
# 5       122     255     147     6       255     255     0
# 6       255     255     0       7       255     200     0
# 7       255     200     0       8       255     145     0
# 8       255     145     0       9       255     0       0
# 9       255     0       0       10      200     0       0
# 10      200     0       0       13      128     0       0

cdict = {'red': ((0.0,1.00,1.0),
                  (0.1,1.00,0.75),
                  (0.2,0.75,0.63),
                  (0.3,0.63,0.50),
                  (0.4,0.50,0.48),
                  (0.5,0.48,1.00),
                  (0.6,1.00,1.00),
                  (0.7,1.00,1.00),
                  (0.8,1.00,1.00),
                  (0.9,1.00,0.78),
                  (1.0,0.78,0.50)),
          'green': ((0.0,1.00,1.00),
                    (0.1,1.00,0.80),
                    (0.2,0.80,0.90),
                    (0.3,0.90,1.00),
                    (0.4,1.00,1.00),
                    (0.5,1.00,1.00),
                    (0.6,1.00,0.78),
                    (0.7,0.78,0.57),
                    (0.8,0.57,0.00),
                    (0.9,0.00,0.00),
                    (1.0,0.00,0.00)),
          'blue': ((0.0,1.00,1.00),
                   (0.1,1.00,1.00),
                   (0.2,1.00,1.00),
                   (0.3,1.00,1.00),
                   (0.4,1.00,0.58),
                   (0.5,0.58,0.00),
                   (0.6,0.00,0.00),
                   (0.7,0.00,0.00),
                   (0.8,0.00,0.00),
                   (0.9,0.00,0.00),
                   (1.0,0.00,0.00))}

my_cmap = matplotlib.colors.LinearSegmentedColormap('my_colormap',cdict)
pcolor(rand(10,10),cmap=my_cmap)
colorbar()
savefig('colormap.png')





------------------------------------------------------
Michael Hearne
mh...@us...
(303) 273-8620
USGS National Earthquake Information Center
1711 Illinois St. Golden CO 80401
Senior Software Engineer
Synergetics, Inc.
------------------------------------------------------