matplotlib create broken axis in subplot

Question

I have a problematic subplot that has two scales of data. Instead of using a log scale, I want to break the axis, so that half of the subplot y axis runs from 0 to 10 and the other half from 10 to 100.

import numpy as np
import matplotlib.pyplot as plt
x = np.random.uniform(0, 10, 40)
y = np.concatenate([np.random.uniform(0, 1, 30), np.random.uniform(0, 100, 10)])
y2 = np.random.uniform(0, 1, 40) 
fig, ax = plt.subplots(2, sharex=True)
ax[0].scatter(x, y) # problematic subplot
ax[1].scatter(x, y2)
plt.show()

I tried following pyplot's broken axis demo, though this seems wrong. Do I need to create a total of four subplots to do this? This is just a dummy example, my real problem has several subplots, many of which need these broken axis.

import numpy as np
import matplotlib.pyplot as plt
x = np.random.uniform(0, 10, 40)
y = np.concatenate([np.random.uniform(0, 1, 30), np.random.uniform(0, 100, 10)])
y2 = np.random.uniform(0, 1, 40) 

fig, ax = plt.subplots(4, sharex=True)

# Create broken axis with first two subplots
ax[0].scatter(x, y)
ax[1].scatter(x, y)
ax[0].set_ylim(1, 100)
ax[1].set_ylim(0, 1)
ax[0].spines['bottom'].set_visible(False)
ax[1].spines['top'].set_visible(False)

# From https://matplotlib.org/examples/pylab_examples/broken_axis.html
d = .015  # how big to make the diagonal lines in axes coordinates
# arguments to pass to plot, just so we don't keep repeating them
kwargs = dict(transform=ax[0].transAxes, color='k', clip_on=False)
ax[0].plot((-d, +d), (-d, +d), **kwargs)        # top-left diagonal
ax[0].plot((1 - d, 1 + d), (-d, +d), **kwargs)  # top-right diagonal

kwargs.update(transform=ax[1].transAxes)  # switch to the bottom axes
ax[0].plot((-d, +d), (1 - d, 1 + d), **kwargs)  # bottom-left diagonal
ax[0].plot((1 - d, 1 + d), (1 - d, 1 + d), **kwargs)  # bottom-right diagonal



# Try my best to fix bottom two plots so they look like one plot
ax[2].scatter(x, y2)
ax[3].scatter(x, y2)
ax[2].set_ylim(.5, 1.0)
ax[3].set_ylim(0, .5)
ax[2].spines['bottom'].set_visible(False)
ax[3].spines['top'].set_visible(False)
plt.savefig('ex.pdf')

It's not really clear if you want the upper graph as a broken axes or both plots as a broken axes. Can you describe what exactly you want to achieve and what makes your currect plot "ugly"? — ImportanceOfBeingErnest
– ImportanceOfBeingErnest, Commented Jun 23, 2017 at 23:28
@ImportanceOfBeingErnest I only want the top plot to be broken. In the bottom subplot, the axis should be continuous, not have two 0.5 points. — kilojoules
– kilojoules, Commented Jun 23, 2017 at 23:30

Laxsnor · Accepted Answer · 2020-04-27 15:47:58Z

10

I might suggest to use only two subplots, one at the top and one at the bottom. Then, divide the upper one into two via mpl_toolkits.axes_grid1.make_axes_locatable.

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


x = np.random.uniform(0, 10, 40)
y = np.concatenate([np.random.uniform(0, 1, 30), np.random.uniform(0, 100, 10)])
y2 = np.random.uniform(0, 1, 40) 

fig, axes = plt.subplots(nrows=2, sharex=True)

ax = axes[0]
divider = make_axes_locatable(ax)
ax2 = divider.new_vertical(size="100%", pad=0.1)
fig.add_axes(ax2)

ax.scatter(x, y)
ax.set_ylim(0, 1)
ax.spines['top'].set_visible(False)
ax2.scatter(x, y)
ax2.set_ylim(10, 100)
ax2.tick_params(bottom=False, labelbottom=False)
ax2.spines['bottom'].set_visible(False)


# From https://matplotlib.org/examples/pylab_examples/broken_axis.html
d = .015  # how big to make the diagonal lines in axes coordinates
# arguments to pass to plot, just so we don't keep repeating them
kwargs = dict(transform=ax2.transAxes, color='k', clip_on=False)
ax2.plot((-d, +d), (-d, +d), **kwargs)        # top-left diagonal
ax2.plot((1 - d, 1 + d), (-d, +d), **kwargs)  # top-right diagonal

kwargs.update(transform=ax.transAxes)  # switch to the bottom axes
ax.plot((-d, +d), (1 - d, 1 + d), **kwargs)  # bottom-left diagonal
ax.plot((1 - d, 1 + d), (1 - d, 1 + d), **kwargs)  # bottom-right diagonal


#create bottom subplot as usual
axes[1].scatter(x, y2)


plt.show()

edited Apr 27, 2020 at 15:47

Laxsnor

8671 gold badge12 silver badges22 bronze badges

answered Jun 24, 2017 at 0:33

ImportanceOfBeingErnest

342k61 gold badges737 silver badges771 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Zee Over a year ago

How to add a common yaxis label to both the spines? A shared label for ax and ax2 in between?

Collectives™ on Stack Overflow

matplotlib create broken axis in subplot

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related