Python module to plot chord diagrams with matplotlib.
The code is hosted on Codeberg's Gitea and mirrored on GitHub. Please raise any issue you encouter on the issue tracker.
Note that the repository has this structure (everything is on root level) to be able to be used more easily as a git submodule.
An example can be found in file example.py.
Here is what the diagrams look like:
- Upper left > no gradient, no gap, default colormap, default order
- Upper right > gradient, no gap, "summer" colormap, rotated names, sorted by distance
- Lower left > no gradient but gap, single color for chords, rotated names, sorted by distance
- Lower right > gradient and gap, default colormap, default order
def chord_diagram(mat, names=None, order=None, width=0.1, pad=2., gap=0.03,
chordwidth=0.7, ax=None, colors=None, cmap=None, alpha=0.7,
use_gradient=False, chord_colors=None, show=False, **kwargs):
"""
Plot a chord diagram.
Parameters
----------
mat : square matrix
Flux data, mat[i, j] is the flux from i to j
names : list of str, optional (default: no names)
Names of the nodes that will be displayed (must be ordered as the
matrix entries).
order : list, optional (default: order of the matrix entries)
Order in which the arcs should be placed around the trigonometric
circle.
width : float, optional (default: 0.1)
Width/thickness of the ideogram arc.
pad : float, optional (default: 2)
Distance between two neighboring ideogram arcs. Unit: degree.
gap : float, optional (default: 0)
Distance between the arc and the beginning of the cord.
chordwidth : float, optional (default: 0.7)
Position of the control points for the chords, controlling their shape.
ax : matplotlib axis, optional (default: new axis)
Matplotlib axis where the plot should be drawn.
colors : list, optional (default: from `cmap`)
List of user defined colors or floats.
cmap : str or colormap object (default: viridis)
Colormap that will be used to color the arcs and chords by default.
See `chord_colors` to use different colors for chords.
alpha : float in [0, 1], optional (default: 0.7)
Opacity of the chord diagram.
use_gradient : bool, optional (default: False)
Whether a gradient should be use so that chord extremities have the
same color as the arc they belong to.
chord_colors : str, or list of colors, optional (default: None)
Specify color(s) to fill the chords differently from the arcs.
When the keyword is not used, chord colors default to the colomap given
by `colors`.
Possible values for `chord_colors` are:
* a single color (do not use an RGB tuple, use hex format instead),
e.g. "red" or "#ff0000"; all chords will have this color
* a list of colors, e.g. ``["red", "green", "blue"]``, one per node
(in this case, RGB tuples are accepted as entries to the list).
Each chord will get its color from its associated source node, or
from both nodes if `use_gradient` is True.
show : bool, optional (default: False)
Whether the plot should be displayed immediately via an automatic call
to `plt.show()`.
kwargs : keyword arguments
Available kwargs are:
================ ================== ===============================
Name Type Purpose and possible values
================ ================== ===============================
fontcolor str or list Color of the names
fontsize int Size of the font for names
rotate_names (list of) bool(s) Rotate names by 90°
sort str Either "size" or "distance"
zero_entry_size float Size of zero-weight reciprocal
================ ================== ===============================
"""Install using
pip install mpl-chord-diagram
then, in python script or terminal:
from mpl_chord_diagram import chord_diagramThe code requires numpy, scipy and matplotlib, which should be
installed automatically. If necessary, you can also install them by calling
pip install -r requirements.txt