Re: [Matplotlib-users] how to draw concentric donuts chart ?

[Joe K. <jof...@gm...>]

On Fri, May 16, 2014 at 7:36 AM, Alan G Isaac <ala...@gm...> wrote:

> On 5/16/2014 7:51 AM, 不坏阿峰 wrote:
> > how to use matplotlib to drew chart like this ?
> > http://www.advsofteng.com/doc/cdpydoc/images/concentric.png
>
>
> Not an answer to your question:
> http://www.businessinsider.com/pie-charts-are-the-worst-2013-6
>
> fwiw,
> Alan Isaac
>

Alan is quite right. However, that aside, here's how you'd do it in
matplotlib:

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.axis('equal')

# Width of the "rings" (percentages if the largest "radius"==1)
width = 0.35

# Note the different "radius" values: largest --> outside "donut".
kwargs = dict(colors=['#66FF66', '#9999FF', '#FF9999'], startangle=90)
inside, _ = ax.pie([45, 87, 77], radius=1-width, **kwargs)
outside, _ = ax.pie([96, 124, 88], radius=1, **kwargs)

# This is the key. We'll set the "width" for all wedges generated by ax.pie.
# (The inside radius for each donut will be "radius" - "width")
plt.setp(inside + outside, width=width, edgecolor='white')

ax.legend(inside[::-1], ['Hardware', 'Software', 'Services'], frameon=False)

plt.show()



If you wanted to replicate the example figure more closely, you'll need to
get a touch fancier:

import matplotlib.pyplot as plt
import numpy as np

def pie(ax, values, **kwargs):
    total = sum(values)
    def formatter(pct):
        return '${:0.0f}M\n({:0.1f}%)'.format(pct*total/100, pct)
    wedges, _, labels = ax.pie(values, autopct=formatter, **kwargs)
    return wedges

fig, ax = plt.subplots()
ax.axis('equal')

width = 0.35
kwargs = dict(colors=['#66FF66', '#9999FF', '#FF9999'], startangle=90)

outside = pie(ax, [96, 124, 88], radius=1, pctdistance=1-width/2, **kwargs)
inside = pie(ax, [45, 87, 77], radius=1-width,
             pctdistance=1 - (width/2) / (1-width), **kwargs)
plt.setp(inside + outside, width=width, edgecolor='white')

ax.legend(inside[::-1], ['Hardware', 'Software', 'Services'], frameon=False)

kwargs = dict(size=13, color='white', va='center', fontweight='bold')
ax.text(0, 0, 'Year 2005', ha='center',
        bbox=dict(boxstyle='round', facecolor='blue', edgecolor='none'),
        **kwargs)
ax.annotate('Year 2006', (0, 0), xytext=(np.radians(-45), 1.1),
            bbox=dict(boxstyle='round', facecolor='green',
edgecolor='none'),
            textcoords='polar', ha='left', **kwargs)

plt.show()



Hope those examples give you some ideas!
Cheers,
-Joe
​