Two-Dimensional Dictionary in Pie Chart

[OleKristian]

Hi! I am trying to make a two-dimensional pie plot with Bokeh and Pandas.
I have been following Bokeh’s documentation on creating a regular pie chart, which works great. I want to expand on the example found in the documentation by segmenting the different countries in their respective continent, like so:

x = {
    "Africa": {
        "Egypt": 157,
        "Kenya": 35,
        "Morocco": 32,
        "Nigeria": 93
    },
    "Asia": {
        "China": 63,
        "India": 42,
        "Japan": 89,
        "Taiwan": 31
    },
    "Europe": {
        "France": 31,
        "Germany": 44,
        "Italy": 40,
        "Spain": 29
    }
}

I want a pie plot where there is an inner diagram for the continents and sub-segments on the outside representing the individual countries.

I’ve tried making DataFrames in Pandas with the original example, aswell as with my own data set, but I’m starting to believe that I need to create different pie charts that I overlay with one another to get the results I’m wanting as nested dictionaries or lists don’t yield proper DataFrames.

import pandas

# The data we have to work with.
x = {
    'United States': 157,
    'United Kingdom': 93,
    'Japan': 89,
    'China': 63,
    'Germany': 44,
    'India': 42,
    'Italy': 40,
    'Australia': 35,
    'Brazil': 32,
    'France': 31,
    'Taiwan': 31,
    'Spain': 29,
}

# Building the DataFrame using Pandas.
data = pandas.Series(x).reset_index(name = 'value').rename(columns = { 'index': 'country' })

print(data)

Will yield:

country	value
United States	157
United Kingdom	93
Japan	89
China	63
Germany	44
India	42
Italy	40
Australia	35
Brazil	32
France	31
Taiwan	31
Spain	29

If I replace the data set with my custom dictionary, I instead get:

country	value
Africa	{‘Egypt’: 157, ‘Kenya’: 35, ‘Morocco’: 32, 'Ni…
Asia	{‘China’: 63, ‘India’: 42, ‘Japan’: 89, 'Taiwa…
Europe	{‘France’: 31, ‘Germany’: 44, ‘Italy’: 40, 'Sp…

Any help would be greatly appreciated.

[Bryan]

In order to do this, you will need to construct a pie chart with wedge glyphs for the inner part, and a donut chart with annular wedge glyphs for the outer part. There used to be an example of this in the repo, but it was removed since it was a bit more complicated than we like our example code to be. However you can still see the code by navigating to the old release tag:

bokeh/examples/models/file/donut.py at 2.4.3 · bokeh/bokeh · GitHub

I just just checked that this code still runs as-is with latest Bokeh 3.6.2 and generates the output below. Note that this code uses the lower level bokeh.models API directly. I don’t have anything similar to share that uses bokeh.plotting instead. Still, hopefully this is a useful reference.