matplotlib matshow colorbar discrete setting

링크 : https://stackoverflow.com/questions/18704353/correcting-matplotlib-colorbar-ticks

샘플 코드

# -*- coding: utf-8 -*-

import numpy as np

import matplotlib as mpl

#mpl.use('Agg')

import matplotlib.pyplot as plt

import matplotlib.cm as cm

import matplotlib.colors as mcolors

tick_label = [ "{}".format(i) for i in range(35)]

def colorbar_index(ncolors, cmap, fig):

cmap = cmap_discretize(cmap, ncolors)

mappable = cm.ScalarMappable(cmap=cmap)

mappable.set_array([])

mappable.set_clim(-0.5, ncolors+0.5)

return mappable, cmap

def cmap_discretize(cmap, N):

"""Return a discrete colormap from the continuous colormap cmap.

cmap: colormap instance, eg. cm.jet.

N: number of colors.

Example

x = resize(arange(100), (5,100))

djet = cmap_discretize(cm.jet, 5)

imshow(x, cmap=djet)

"""

if type(cmap) == str:

cmap = plt.get_cmap(cmap)

colors_i = np.concatenate((np.linspace(0, 1., N), (0.,0.,0.,0.)))

colors_rgba = cmap(colors_i)

colors_rgba[0] = [0,0,0,1]

indices = np.linspace(0, 1., N+1)

cdict = {}

for ki,key in enumerate(('red','green','blue')):

cdict[key] = [ (indices[i], colors_rgba[i-1,ki],

colors_rgba[i,ki]) for i in xrange(N+1) ]

# Return colormap object.

return mcolors.LinearSegmentedColormap(cmap.name +

"_%d"%N, cdict, 1024)

f = plt.figure()

axarr = []

axarr.append(f.add_subplot(4,1,1))

axarr.append(f.add_subplot(4,1,2))

axarr.append(f.add_subplot(4,1,3))

#axarr.append(f.add_subplot(3,1, 2))

ncolors = 34

mappable, cmap = colorbar_index(ncolors=ncolors, cmap=plt.cm.Paired, fig=f)

for i in range(3):

m_input_list = [range(0,ncolors),range(0,ncolors),range(0,ncolors)]

cax = axarr[i].matshow(m_input_list, cmap=cmap, vmin=0, vmax=33,

interpolation='none')

axarr[i].axis('tight')

axarr[i].tick_params(labeltop= False,

labelbottom= False,

labelleft=False,

labelright=False,

left=False,

right=False,

bottom=False,

top=False)

axarr[i].set_ylabel('Raw data', fontsize=7)

# axarr[i].set_xticks(range(0,ncolors))

# axarr[i].set_xticklabels(["{}".format(x)

for x in range(0, ncolors)], size=6)

f.subplots_adjust(right=0.78, left=0.05)

cbar_ax = f.add_axes([0.80,0.05,0.02,0.9])

colorbar = plt.colorbar(mappable, cax=cbar_ax)

colorbar.ax.tick_params(labelsize=7)

colorbar.set_ticks(np.linspace(0, ncolors, ncolors))

colorbar.set_ticklabels(tick_label)

plt.show()