matplotlib example arcs (snippet)

Python matplotlib example 'arcs'

Functions in program:

• def arcs(x, y, w, h=None, rot=0.0, theta1=0.0, theta2=360.0,

Modules used in program:

• import matplotlib.pyplot as plt
• import numpy as np

python arcs

Python matplotlib example: arcs

from __future__ import division, print_function, absolute_import
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Arc
from matplotlib.collections import PatchCollection

__all__ = ['arcs']

def arcs(x, y, w, h=None, rot=0.0, theta1=0.0, theta2=360.0,
         c='b', vmin=None, vmax=None, **kwargs):
    """
    Make a scatter plot of Arcs. 

    Parameters
    ----------
    x, y : scalar or array_like, shape (n, )
        Center of ellipses.
    w, h : scalar or array_like, shape (n, )
        Total length (diameter) of horizontal/vertical axis.
        `h` is set to be equal to `w` by default, ie. circle.
    rot : scalar or array_like, shape (n, )
        Rotation in degrees (anti-clockwise).
    c : color or sequence of color, optional, default : 'b'
        `c` can be a single color format string, or a sequence of color
        specifications of length `N`, or a sequence of `N` numbers to be
        mapped to colors using the `cmap` and `norm` specified via kwargs.
        Note that `c` should not be a single numeric RGB or RGBA sequence
        because that is indistinguishable from an array of values
        to be colormapped. (If you insist, use `color` instead.)
        `c` can be a 2-D array in which the rows are RGB or RGBA, however.
    vmin, vmax : scalar, optional, default: None
        `vmin` and `vmax` are used in conjunction with `norm` to normalize
        luminance data.  If either are `None`, the min and max of the
        color array is used.
    kwargs : `~matplotlib.collections.Collection` properties
        Eg. alpha, edgecolor(ec), facecolor(fc), linewidth(lw), linestyle(ls),
        norm, cmap, transform, etc.

    Returns
    -------
    paths : `~matplotlib.collections.PathCollection`

    Examples
    --------
    a = np.arange(11)
    arcs(a, a, w=4, h=a, rot=a*30, theta1=0.0, theta2=180.0, 
         c=a, alpha=0.5, ec='none')
    plt.colorbar()

    License
    --------
    This code is under [The BSD 3-Clause License]
    (http://opensource.org/licenses/BSD-3-Clause)
    """
    if np.isscalar(c):
        kwargs.setdefault('color', c)
        c = None

    if 'fc' in kwargs:
        kwargs.setdefault('facecolor', kwargs.pop('fc'))
    if 'ec' in kwargs:
        kwargs.setdefault('edgecolor', kwargs.pop('ec'))
    if 'ls' in kwargs:
        kwargs.setdefault('linestyle', kwargs.pop('ls'))
    if 'lw' in kwargs:
        kwargs.setdefault('linewidth', kwargs.pop('lw'))
    # You can set `facecolor` with an array for each patch,
    # while you can only set `facecolors` with a value for all.

    if h is None:
        h = w

    zipped = np.broadcast(x, y, w, h, rot, theta1, theta2)
    patches = [Arc((x_, y_), w_, h_, rot_, t1_, t2_)
               for x_, y_, w_, h_, rot_, t1_, t2_ in zipped]
    collection = PatchCollection(patches, **kwargs)
    if c is not None:
        c = np.broadcast_to(c, zipped.shape).ravel()
        collection.set_array(c)
        collection.set_clim(vmin, vmax)

    ax = plt.gca()
    ax.add_collection(collection)
    ax.autoscale_view()
    plt.draw_if_interactive()
    if c is not None:
        plt.sci(collection)
    return collection

Python links

• Learn Python: https://pythonbasics.org/
• Python Tutorial: https://pythonprogramminglanguage.com