颜色条设置刻度格式器/定位器更改刻度标签

Question

用户，我想自定义颜色栏上的记号。然而，我发现了以下奇怪的行为。我试图将tick格式化程序更改为默认格式化程序（我认为这应该不会改变任何内容），但最终得到了不同的标签。有人知道我做错了什么吗？或者这是一个bug？

我使用git中的matplotlib（v10.1-961-gb516ae0，git-descripte）。以下代码生成两个图：

#http://matplotlib.sourceforge.net/examples/pylab_examples/griddata_demo.html
from numpy.random import uniform, seed
from matplotlib.mlab import griddata
import matplotlib.pyplot as plt
import matplotlib.ticker
import numpy as np
# make up data.
seed(0)
npts = 200
x = uniform(-2,2,npts)
y = uniform(-2,2,npts)
z = x*np.exp(-x**2-y**2)
# define grid
xi = np.linspace(-2.1,2.1,100)
yi = np.linspace(-2.1,2.1,200)
# grid the data.
zi = griddata(x,y,z,xi,yi,interp='linear')
##### FIRST PLOT
plt.figure()
CS  = plt.contour(xi,yi,zi,25,cmap=plt.cm.jet)
bar = plt.colorbar() # draw colorbar
# plot data points.
#plt.scatter(x,y,marker='o',c='b',s=5,zorder=10)
plt.xlim(-2,2)
plt.ylim(-2,2)
plt.title('griddata test (%d points)' % npts)
plt.show()
##### SECOND PLOT
plt.figure()
CS  = plt.contour(xi,yi,zi,25,cmap=plt.cm.jet)
bar = plt.colorbar() # draw colorbar
bar.ax.yaxis.set_minor_locator(matplotlib.ticker.AutoLocator())
bar.ax.yaxis.set_major_locator(matplotlib.ticker.AutoLocator())
# plot data points.
#plt.scatter(x,y,marker='o',c='b',s=5,zorder=10)
plt.xlim(-2,2)
plt.ylim(-2,2)
plt.title('griddata test (%d points)' % npts)
plt.show()

Answer 1

我刚刚找到了解决方案。必须呼叫

bar.update_ticks()

更改格式化程序/定位器后，请参阅

http://matplotlib.sourceforge.net/api/colorbar_api.html

然后一切都很好。

更新：

这也是更改格式化程序/定位器的代码。它基于彩色条形码的内部结构，所以也许其他人有更好的解决方案：

#http://matplotlib.sourceforge.net/examples/pylab_examples/griddata_demo.html
from numpy.random import uniform, seed
from matplotlib.mlab import griddata
import matplotlib.pyplot as plt
import matplotlib.ticker
import numpy as np
# make up data.
seed(0)
npts = 200
x = uniform(-2,2,npts)
y = uniform(-2,2,npts)
z = x*np.exp(-x**2-y**2)
# define grid
xi = np.linspace(-2.1,2.1,100)
yi = np.linspace(-2.1,2.1,200)
# grid the data.
zi = griddata(x,y,z,xi,yi,interp='linear')
##### PLOT
plt.figure()
CS  = plt.contour(xi,yi,zi,25,cmap=plt.cm.jet)
bar = plt.colorbar(orientation='horizontal') # draw colorbar

tick_locs   = [-3.9e-1,-2.6e-1,-1.3e-1,0e-1,1.3e-1,2.6e-1,3.9e-1]
tick_labels = ['-0.390','-0.260','-0.130','0','0.13','0.26','0.390']

bar.locator     = matplotlib.ticker.FixedLocator(tick_locs)
bar.formatter   = matplotlib.ticker.FixedFormatter(tick_labels)
bar.update_ticks()
# plot data points.
#plt.scatter(x,y,marker='o',c='b',s=5,zorder=10)
plt.xlim(-2,2)
plt.ylim(-2,2)
plt.title('griddata test (%d points)' % npts)
plt.show()