python - How can I change the font size using seaborn FacetGrid?

68
votes

I have plotted my data with factorplot in seaborn and get facetgrid object, but still cannot understand how the following attributes could be set in such a plot:

  1. Legend size: when I plot lots of variables, I get very small legends, with small fonts.
  2. Font sizes of y and x labels (a similar problem as above)
4
pythonseaborn
The responses below are correct and should help you out, but I would say it sounds like you're plotting in the IPython notebook and so the issue isn't really anything to do with seaborn but that the notebook scales down figures if they end up larger than the div allotted to them. If you save the figure, everything should be the size that you expect. - mwaskom
Also if you are plotting a lot of variables on the columns and don't have a row variable, you could use col_wrap to "wrap" the facets onto multiple rows, which might help. - mwaskom

4 Answers

124
votes

You can scale up the fonts in your call to sns.set().

import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
x = np.random.normal(size=37)
y = np.random.lognormal(size=37)

# defaults
sns.set()
fig, ax = plt.subplots()
ax.plot(x, y, marker='s', linestyle='none', label='small')
ax.legend(loc='upper left', bbox_to_anchor=(0, 1.1))

enter image description here

sns.set(font_scale=5)  # crazy big
fig, ax = plt.subplots()
ax.plot(x, y, marker='s', linestyle='none', label='big')
ax.legend(loc='upper left', bbox_to_anchor=(0, 1.3))

enter image description here

46
votes

The FacetGrid plot does produce pretty small labels. While @paul-h has described the use of sns.set as a way to the change the font scaling, it may not be the optimal solution since it will change the font_scale setting for all plots.

You could use the seaborn.plotting_context to change the settings for just the current plot:

with sns.plotting_context(font_scale=1.5):
    sns.factorplot(x, y ...)
14
votes

I've made small modifications to @paul-H code, such that you can set the font size for the x/y axes and legend independently. Hope it helps:

import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
x = np.random.normal(size=37)
y = np.random.lognormal(size=37)

# defaults                                                                                                         
sns.set()
fig, ax = plt.subplots()
ax.plot(x, y, marker='s', linestyle='none', label='small')
ax.legend(loc='upper left', fontsize=20,bbox_to_anchor=(0, 1.1))
ax.set_xlabel('X_axi',fontsize=20);
ax.set_ylabel('Y_axis',fontsize=20);

plt.show()

This is the output:

enter image description here

7
votes

For the legend, you can use this 

plt.setp(g._legend.get_title(), fontsize=20)

Where g is your facetgrid object returned after you call the function making it.