Matplotlib, one colorbar for all subplots, overlay on papersize

Question

I´ve got the following problem, that my colorbar overlays my papersized subplots that are "printed" as an pdf.

Code example:

import numpy as np

import matplotlib.pyplot as plt

import pandas as pd

if __name__ == '__main__':

    titles = np.random.uniform(low=1, high=11, size=(1,10))
    temp = np.random.uniform(low=23, high=200, size=(10,10))
    ctf0102 = np.random.uniform(low=23, high=200, size=(10,10))
    ctf03 = np.random.uniform(low=23, high=200, size=(10,10))

    fig = plt.figure(figsize=(11.69,8.27), dpi=100)

    for num in range(len(titles)):

        ax = fig.add_subplot(3,4,num)

        im = ax.scatter(ctf03[1:,num], ctf0102[:,num], 12, temp[:,num], cmap='magma')

        ax.set_title(titles[num])


    fig.text(0.5, -0.00, '...', ha='center', fontsize=16)

    fig.text(-0.00, 0.5, '...', va='center', rotation='vertical', fontsize=16)

    cbar_ax = fig.add_axes([0.85, 0.15, 0.05, 0.7])
    fig.colorbar(im, cax=cbar_ax)

    plt.tight_layout(pad=2)

    fig.savefig("example.pdf", dpi=fig.dpi, bbox_inches='tight', pad_inches=0.3)

Any idea how i can move the colorbar to the right, by resizing the space of all my subplots? Besides that i would like to enlarge the colorbar, to become a smooth closing with the top and bottom of all subplots.

Thanks for help and ideas.

Answer 1

Use fig.subplots_adjust to set the bottom, top, left and right position of the subplots. Then use the same bottom and top to define where the colorbar is placed vertically. And make sure the left edge of the colorbar is to the right of the subplots.

Also, you can't use tight_layout here, otherwise it changes the positions.

import numpy as np

import matplotlib.pyplot as plt

import pandas as pd

fig = plt.figure(figsize=(11.69,8.27), dpi=100)

bottom, top = 0.1, 0.9
left, right = 0.1, 0.8

fig.subplots_adjust(top=top, bottom=bottom, left=left, right=right, hspace=0.15, wspace=0.25)

for num in range(12):

    ax = fig.add_subplot(3,4,num+1)
    im = ax.scatter(np.random.rand(10), np.random.rand(10), 12, np.random.rand(10), cmap='magma')

fig.text(0.5, 0.02, 'x label', ha='center', fontsize=16)

fig.text(0.02, 0.5, 'ylabel ', va='center', rotation='vertical', fontsize=16)

cbar_ax = fig.add_axes([0.85, bottom, 0.05, top-bottom])
fig.colorbar(im, cax=cbar_ax)

fig.savefig("example.pdf", dpi=fig.dpi, pad_inches=0.3)