matplotlib-venn 0.2

Functions for plotting area-proportional two- and three-way Venn diagrams in matplotlib.

Routines for plotting area-weighted two- and three-circle venn diagrams.

Installation

The simplest way to install the package is via easy_install or pip:

$ easy_install matplotlib-venn

Dependencies

• numpy, scipy, matplotlib.

Usage

The package provides four main functions: venn2, venn2_circles, venn3 and venn3_circles.

The functions venn2 and venn2_circles accept as their only required argument a 3-element list (Ab, aB, AB) of subset sizes, e.g.:

venn2(subsets = (3, 2, 1))

and draw a two-circle venn diagram with respective region areas. In the particular example, the region, corresponding to subset A and not B will be three times larger in area than the region, corresponding to subset A and B.

Similarly, the functions venn3 and venn3_circles take a 7-element list of subset sizes (Abc, aBc, ABc, abC, AbC, aBC, ABC), and draw a three-circle area-weighted venn diagram.

The functions venn2_circles and venn3_circles draw just the circles, whereas the functions venn2 and venn3 draw the diagrams as a collection of colored patches, annotated with text labels.

Note that for a three-circle venn diagram it is not in general possible to achieve exact correspondence between the required set sizes and region areas, however in most cases the picture will still provide a decent indication.

The functions venn2_circles and venn3_circles return the list of matplotlib.patch.Circle objects that may be tuned further to your liking. The functions venn2 and venn3 return an object of class Venn2 or Venn3 respectively, which gives access to constituent patches and text elements.

Basic Example:

from matplotlib.venn import venn2
venn2(subsets = (3, 2, 1))

For the three-circle case:

from matplotlib.venn import venn3
venn3(subsets = (1, 1, 1, 2, 1, 2, 2), set_labels = ('Set1', 'Set2', 'Set3'))

A more elaborate example:

from matplotlib import pyplot as plt
import numpy as np
from matplotlib.venn import venn3, venn3_circles
plt.figure(figsize=(4,4))
v = venn3(subsets=(1, 1, 1, 1, 1, 1, 1), set_labels = ('A', 'B', 'C'))
v.get_patch_by_id('100').set_alpha(1.0)
v.get_patch_by_id('100').set_color('white')
v.get_label_by_id('100').set_text('Unknown')
v.get_label_by_id('A').set_text('Set "A"')
c = venn3_circles(subsets=(1, 1, 1, 1, 1, 1, 1), linestyle='dashed')
c[0].set_lw(1.0)
c[0].set_ls('dotted')
plt.title("Sample Venn diagram")
plt.annotate('Unknown set', xy=v.get_label_by_id('100').get_position() - np.array([0, 0.05]), xytext=(-70,-70),
            ha='center', textcoords='offset points', bbox=dict(boxstyle='round,pad=0.5', fc='gray', alpha=0.1),
            arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=0.5',color='gray'))

See also

• Blog post: http://fouryears.eu/2012/10/13/venn-diagrams-in-python/

• Report issues and submit fixes at Github: https://github.com/konstantint/matplotlib-venn