I want to create a graph with wavy lines omitted in the middle with matplotlib (I want to manipulate the impression)

Overview

Due to various adult circumstances, you may want to ** omit the middle of the graph with a wavy line **. This is an explanation of how to create such a graph using matplotlib.

Execution environment

We have confirmed the execution and operation with Python 3.6.9 (Google Colab. Environment).

Execution environment

japanize-matplotlib      1.0.5          
matplotlib               3.1.3          
matplotlib-venn          0.11.5         

Preparation for using Japanese in graphs

In order to make matplotlib ** Japanese compatible ** in Google Colab. Environment, do as follows.

Preparation for using Japanese in the graph

!pip install japanize-matplotlib
import japanize_matplotlib

Create a bar chart normally

First, let's draw a bar graph normally.

Create a bar chart normally

left   = np.array(['Fukushima', 'Aichi', 'Kanagawa', 'Osaka', 'Tokyo'])
height = np.array([160, 220, 280, 360, 1820])

plt.figure(figsize=(3,4), dpi=160)
plt.bar(left,height) #bar graph
plt.yticks(np.arange(0,1800+1,200))    #X-axis scale from 0 to 1900 in 200 increments
plt.gcf().patch.set_facecolor('white') #Set the background color to "white"

The execution result is as follows. The protrusion of Tokyo is very noticeable.

Create a bar graph with wavy lines omitted in the middle

Step 1 Arrange the same bar charts up and down in the subplot

Step.1

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
from matplotlib.path import Path

left   = np.array(['Fukushima', 'Aichi', 'Kanagawa', 'Osaka', 'Tokyo'])
height = np.array([160, 220, 280, 360, 1820])

#Subplot Prepare a 2-by-1 subplot
fig, ax = plt.subplots(nrows=2, figsize=(3,4), dpi=160, sharex='col',
                       gridspec_kw={'height_ratios': (1,2)} )

fig.patch.set_facecolor('white') #Set the background color to "white"

ax[0].bar(left,height) #Upper row
ax[1].bar(left,height) #Lower row

gridspec_kw = {'height_ratios': (1,2)} is set so that the height ratio of the top and bottom is $ 1: 2 $. The execution result is as follows.

Step 2 Stick the upper and lower graphs together

There is a gap between the upper and lower subplots, so I will erase it.

Step.2

#Set the vertical spacing between subplots to zero
fig.subplots_adjust(hspace=0.0)  

The execution result is as follows.

Step 3 Erase the border and set the Y-axis range individually at the top and bottom

Hides the borders of the upper and lower graphs (= the bottom of the upper subplot, the top of the lower subplot). It also sets the Y-axis display range and scale for each subplot. At this time, make sure that the ** Y-axis display range ratio ** between the subplots is the same as the 'height_ratios': (1,2) specified in Step.1.

Step.3

#Lower subplot
ax[1].set_ylim(0,400)  #Section width 400
ax[1].set_yticks(np.arange(0,300+1,100))

#Upper subplot
ax[0].set_ylim(1750,1950)  #Section width 200
ax[0].set_yticks((1800,1900))

#Hide the top edge of the lower plot area
ax[1].spines['top'].set_visible(False)

#Hide the bottom of the upper plot area, hide the X-axis scale and labels
ax[0].spines['bottom'].set_visible(False)
ax[0].tick_params(axis='x', which='both', bottom=False, labelbottom=False) 

The execution result is as follows.

Step 4 Draw a Nyoro line

I will draw a nyoro (wavy line) indicating that the middle section is omitted.

Step.4

d1 = 0.02 #X-axis protrusion amount
d2 = 0.03 #Nyoro wave height
wn = 21   #Number of Nyoro waves (specify an odd value)

pp = (0,d2,0,-d2)
px = np.linspace(-d1,1+d1,wn)
py = np.array([1+pp[i%4] for i in range(0,wn)])
p = Path(list(zip(px,py)), [Path.MOVETO]+[Path.CURVE3]*(wn-1))

line1 = mpatches.PathPatch(p, lw=4, edgecolor='black',
                          facecolor='None', clip_on=False,
                          transform=ax[1].transAxes, zorder=10)

line2 = mpatches.PathPatch(p,lw=3, edgecolor='white',
                           facecolor='None', clip_on=False,
                           transform=ax[1].transAxes, zorder=10,
                           capstyle='round')

a = ax[1].add_patch(line1)
a = ax[1].add_patch(line2)

The execution result is as follows.

Setting the drawing parameters as d1 = 0.1, wn = 41 gives:

Whole code

Whole code

%reset -f
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
from matplotlib.path import Path

left   = np.array(['Fukushima', 'Aichi', 'Kanagawa', 'Osaka', 'Tokyo'])
height = np.array([160, 220, 280, 360, 1820])

#Subplot Prepare a 2-by-1 subplot
fig, ax = plt.subplots(nrows=2, figsize=(3,4), dpi=160, sharex='col',
                       gridspec_kw={'height_ratios': (1,2)} )

fig.patch.set_facecolor('white') #Set the background color to "white"

ax[0].bar(left,height) #Upper row
ax[1].bar(left,height) #Lower row

#Set the vertical spacing between subplots to zero
fig.subplots_adjust(hspace=0.0)  

#Lower subplot
ax[1].set_ylim(0,400)  #Section width 400
ax[1].set_yticks(np.arange(0,300+1,100))

#Upper subplot
ax[0].set_ylim(1750,1950)  #Section width 200
ax[0].set_yticks((1800,1900))

#Hide the top edge of the lower plot area
ax[1].spines['top'].set_visible(False)

#Hide the bottom of the upper plot area, hide the X-axis scale and labels
ax[0].spines['bottom'].set_visible(False)
ax[0].tick_params(axis='x', which='both', bottom=False, labelbottom=False) 

##Nyoro line drawing
d1 = 0.02 #X-axis protrusion amount
d2 = 0.03 #Nyoro wave height
wn = 21   #Number of Nyoro waves (specify an odd value)

pp = (0,d2,0,-d2)
px = np.linspace(-d1,1+d1,wn)
py = np.array([1+pp[i%4] for i in range(0,wn)])
p = Path(list(zip(px,py)), [Path.MOVETO]+[Path.CURVE3]*(wn-1))

line1 = mpatches.PathPatch(p, lw=4, edgecolor='black',
                          facecolor='None', clip_on=False,
                          transform=ax[1].transAxes, zorder=10)

line2 = mpatches.PathPatch(p,lw=3, edgecolor='white',
                           facecolor='None', clip_on=False,
                           transform=ax[1].transAxes, zorder=10,
                           capstyle='round')

a = ax[1].add_patch(line1)
a = ax[1].add_patch(line2)