将子图与颜色条对齐

Question

我正在尝试共享必须是正方形和经典图的 imshow 的 x 轴：

1. imshow 必须是方形的
2. 带有颜色条
3. 下面的图应该共享相同的轴（或者至少看起来与 imshow 对齐）

我花了两天时间，现在我疯了。有人知道如何对齐它们吗？

用于生成图像的代码如下。

def myplot( Nbin=20 ):

X = np.random.rand(1000)
Y = np.random.rand(1000)
h2, yh2, xh2 = np.histogram2d( Y, X, bins=[Nbin,Nbin] )
h1, xh1 = np.histogram( X, bins=Nbin )
######################################
######################################
fig = plt.figure(  )
gs = gridspec.GridSpec( 3, 2 )
######################################
######################################
ax1 = plt.subplot( gs[:-1,:] )
im = plt.imshow( h2, interpolation='nearest', origin='lower',
                 extent=[xh2[0],xh2[-1],yh2[0],yh2[-1]] )
cb = plt.colorbar( im, ax=ax1 )
plt.xlim( xh1[0], xh1[-1] )
plt.ylim( xh1[0], xh1[-1] )
ax1.tick_params( axis='x', which='both', bottom='on', top='on', labelbottom='off' )
######################################
######################################
ax2 = plt.subplot( gs[-1,:] )
plt.plot( xh1[:-1] + np.diff(xh1)/2., h1 )
plt.xlim( xh1[0], xh1[-1] )
cm = plt.cm.Blues
cb2 = plt.colorbar( ax=ax2 )
ax2.tick_params( axis='x', which='both', bottom='on', top='on', labelbottom='on' )
######################################
######################################
fig.tight_layout()
fig.subplots_adjust(hspace=0.05)
cb2.ax.set_visible(False)

Answer 1

我可以想象将第二个轴直接放在图像下方的最简单方法是使用mpl_toolkits.axes_grid1.make_axes_locatable。这允许以牺牲新创建的子图为代价来缩小图像，并且同样可以用于定位颜色条。

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable

Nbin=20

X = np.random.rand(1000)
Y = np.random.rand(1000)
h2, yh2, xh2 = np.histogram2d( Y, X, bins=[Nbin,Nbin] )
h1, xh1 = np.histogram( X, bins=Nbin )

fig = plt.figure(  )


ax1 = plt.subplot(111)
im = ax1.imshow( h2, interpolation='nearest', origin='lower',
                 extent=[xh2[0],xh2[-1],yh2[0],yh2[-1]] )

plt.xlim( xh1[0], xh1[-1] )
plt.ylim( xh1[0], xh1[-1] )
ax1.tick_params( axis='x', which='both', bottom='on', top='on', labelbottom='off' )


divider = make_axes_locatable(ax1)
ax2 = divider.append_axes("bottom", size="50%", pad=0.08)
cax = divider.append_axes("right", size="5%", pad=0.08)
cb = plt.colorbar( im, ax=ax1, cax=cax )

#ax2 = plt.subplot( gs[-1,:] )  # , sharex=ax1
ax2.plot( xh1[:-1] + np.diff(xh1)/2., h1 )
ax2.set_xlim( xh1[0], xh1[-1] )
cm = plt.cm.Blues

ax2.tick_params( axis='x', which='both', bottom='on', top='on', labelbottom='on' )

plt.show()