Equal spacing between pie charts of different sizes in matplotlib - python-3.x

Question

I am having difficulties with setting an equal space between pie charts of different sizes. The 5 are correctly arranged in one row, but the distance between the contours of neighboring pies aren't equal. I tried many abbreviations of the following code, all of them not making a big difference in the output (see image):
#code:
import matplotlib.pyplot as plt
import pandas as pd
labels = 'Verkehr', 'Maschinen und Motoren', 'Feuerungen', 'Industrie / Gewerbe', 'Land- und Forstwirtschaft'
sizesax1 = [108295, 10107, 7220, 11551, 7220]
sizesax2 = [77882, 6676, 6676, 13351, 6676]
sizesax3 = [55652, 4417, 6184, 15900, 6184]
sizesax4 = [36327, 2642, 4632, 16512, 5944]
sizesax5 = [18781, 1409, 3287, 1878, 4695]
fig, (ax1, ax2, ax3, ax4, ax5) = plt.subplots(1, 5, figsize =(20,4))
ax1.pie(sizesax1, startangle=0, colors = ('red', 'darkblue', 'orange', 'yellow', 'green'), radius=1*4)
ax2.pie(sizesax2, startangle=0, colors = ('red', 'darkblue', 'orange', 'yellow', 'green'), radius=.77*4)
ax3.pie(sizesax3, startangle=0, colors = ('red', 'darkblue', 'orange', 'yellow', 'green'), radius=.61*4)
ax4.pie(sizesax4, startangle=0, colors = ('red', 'darkblue', 'orange', 'yellow', 'green'), radius=.46*4)
ax5.pie(sizesax5, startangle=0, colors = ('red', 'darkblue', 'orange', 'yellow', 'green'), radius=.33*4)
some additions i tried:
fig.subplots_adjust(left=None, bottom=None, right=None, top=None, wspace=1, hspace=None)
or
fig.tight_layout()
#giving me this error message:
/srv/conda/envs/notebook/lib/python3.7/site-packages/ipykernel_launcher.py:17: UserWarning:
Tight layout not applied. The bottom and top margins cannot be made large enough to
accommodate all axes decorations.
and some others.
Big thank you already for reading this! I am a complete beginner in python and just managed to come as far as you see in this image:
enter image description here

Answer 1

It is not clear what it is required. I'll assume it is the following image:
Fundamentally, the problem is that the pie needs a square aspect ratio, which is not provided by a row of subplots.
The simplest solution, is to create only one plot and plot there multiple pies with different centres. Something like:
import matplotlib.pyplot as plt
sizes = [ [108295, 10107, 7220, 11551, 7220],
[77882, 6676, 6676, 13351, 6676],
[55652, 4417, 6184, 15900, 6184],
[36327, 2642, 4632, 16512, 5944],
[18781, 1409, 3287, 1878, 4695]]
colors = ('red', 'darkblue', 'orange', 'yellow', 'green')
R = 4
radius = [R*i for i in [1.0, 0.77, 0.61, 0.46, 0.33] ]
wid = sum(radius)*2
hei = R*2
fig, ax = plt.subplots(figsize =(wid,hei))
fig.subplots_adjust(left = 0, right = 1, bottom = 0, top = 1)
y = R
x = 0
for i in range(5):
x += radius[i]
ax.pie(sizes[i], startangle = 0, colors = colors,
radius = radius[i], center = (x,y) )
x += radius[i]
ax.set(xlim =(0,x), ylim=(0,R*2))
plt.savefig("aaa.png")
Notice that my figure aspect ratio is not the (20,4) of the question, which does not hold for the way I interpreted the intended result.
But it might be the case that there is the need of having these in different axes. If so, the idea is:
Use gridspec to create a single row with 5 columns and provide the ratios so that they correspond to the required radius.
Plot the larger pie in the left slot.
In all remaining slots, use a subgrid, dividing into a column of three (sub-)slots.
Set the height ratios so that the middle one ends up with an aspect ratio of a square.
Plot the pies in the middle slots.
Here we go:
import matplotlib.pyplot as plt
sizes = [ [108295, 10107, 7220, 11551, 7220],
[77882, 6676, 6676, 13351, 6676],
[55652, 4417, 6184, 15900, 6184],
[36327, 2642, 4632, 16512, 5944],
[18781, 1409, 3287, 1878, 4695]]
colors = ('red', 'darkblue', 'orange', 'yellow', 'green')
R = 4
radius = [R*i for i in [1.0, 0.77, 0.61, 0.46, 0.33] ]
wid = sum(radius)*2
hei = R*2
ratios = [i/radius[0] for i in radius] # for gridspec
fig = plt.figure(figsize =(wid,hei))
gs = fig.add_gridspec(1, 5,
width_ratios = ratios,
wspace=0, left = 0, right = 1, bottom = 0, top = 1)
ax = fig.add_subplot(gs[0,0])
ax.pie(sizes[0], startangle = 0, colors = colors, radius = 1 )
ax.set(xlim=(-1,1) ,ylim=(-1,1))
for i in range(1,5):
mid = ratios[i]/sum(ratios)*wid
inrat = [(hei-mid)/2, mid, (hei-mid)/2]
ings = gs[0,i].subgridspec(3, 1, hspace=0,
height_ratios = inrat)
ax = fig.add_subplot(ings[1,0])
ax.pie(sizes[i], startangle = 0, colors = colors, radius = 1 )
ax.set(xlim=(-1,1), ylim=(-1,1))
plt.savefig("aaa.png")