Matplotlib showing x-tick labels overlapping

Question

Have a look at the graph below:

It\'s a subplot of this larger figure:

Answer 1

Due to the way text rendering is handled in matplotlib, auto-detecting overlapping text really slows things down. (The space that text takes up can't be accurately calculated until after it's been drawn.) For that reason, matplotlib doesn't try to do this automatically.

Therefore, it's best to rotate long tick labels. Because dates most commonly have this problem, there's a figure method fig.autofmt_xdate() that will (among other things) rotate the tick labels to make them a bit more readable. (Note: If you're using a pandas plot method, it returns an axes object, so you'll need to use ax.figure.autofmt_xdate().)

As a quick example:

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

time = pd.date_range('01/01/2014', '4/01/2014', freq='H')
values = np.random.normal(0, 1, time.size).cumsum()

fig, ax = plt.subplots()
ax.plot_date(time, values, marker='', linestyle='-')

fig.autofmt_xdate()
plt.show()

If we were to leave fig.autofmt_xdate() out:

And if we use fig.autofmt_xdate():