Python - Organisation of 3 subplots with matplotlib

Question

I try to generate 3 subplots for my figure. It seems work but it is not perfectly aligned. How to have the same width between the figure at the bottom et the figures at below?

plt.close()
fig = plt.figure()

ax1 = plt.subplot(211)
ax1.plot(cycles,np.asarray(df_int),'wo',label='')
ax1.plot(cycles,np.asarray(df_proj),'k+',label='')
ax1.legend(loc=2)
#ax1.subplots_adjust(left=0.15)
ax1.set_ylim(0.001,0.004)

ax2 = plt.subplot(223)
i2=ax2.imshow(c,cmap=plt.cm.hot, vmin=-5, vmax=5);#plt.colorbar();plt.clim(-5,5)
cb2=plt.colorbar(i2,ax=ax2,ticks=[-5,0,5],fraction=0.046, pad=0.04,format='%.2f')
cb2.ax.tick_params(labelsize=12)



ax3 = plt.subplot(224)
i3=ax3.imshow(residue_proj,cmap=plt.cm.hot, vmin=-5, vmax=5);#plt.colorbar();plt.clim(-5,5);
cb3=plt.colorbar(i3,ax=ax3,ticks=[-5,0,5],fraction=0.046, pad=0.04,format='%.2f')
cb3.ax.tick_params(labelsize=12)

plt.savefig('test.png', dpi=500,  bbox_inches='tight', pad_inches=0.1)
#plt.show()

Solution 1

This is probably a lot easier if you use GridSpec:

import numpy as np
import matplotlib.pylab as pl
import matplotlib.gridspec as gridspec

# Create 2x2 sub plots
gs = gridspec.GridSpec(2, 2)

pl.figure()
ax = pl.subplot(gs[0, 0]) # row 0, col 0
pl.plot([0,1])

ax = pl.subplot(gs[0, 1]) # row 0, col 1
pl.plot([0,1])

ax = pl.subplot(gs[1, :]) # row 1, span all columns
pl.plot([0,1])

See: http://matplotlib.org/users/gridspec.html

Solution 2

The same as the above answer can be done with a figure object like so:

import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec

# Create 2x2 sub plots
gs = gridspec.GridSpec(2, 2)

fig = plt.figure()
ax1 = fig.add_subplot(gs[0, 0]) # row 0, col 0
ax1.plot([0,1])

ax2 = fig.add_subplot(gs[0, 1]) # row 0, col 1
ax2.plot([0,1])

ax3 = fig.add_subplot(gs[1, :]) # row 1, span all columns
ax3.plot([0,1])

Comments

[dezdichado]

is it at all possible to get the third figure the same size as the other two and centered alone in the second row instead?

[Bart]

I'm sure that's possible, but not something I (or anyone) can easily answer here in a comment. So perhaps ask a question about this instead?