How to fix lines of axes overlapping imshow plot?

user_10950687 0
Viewed 41

When plotting matrices using matplotlib's imshow function the lines of the axes can overlap the actual plot, see the following minimal example (matshow is just a simple wrapper around imshow):

import numpy as np
import matplotlib.pyplot as plt

fig, ax = plt.subplots(figsize=(3,3))
ax.matshow(np.random.random((50, 50)), interpolation="none", cmap="Blues")
plt.savefig("example.png", dpi=300)

matplotlib.axes.Axes.imshow example with 50x50 random data

I would expect every entry of the matrix to be represented by a square, but in the top row it is quite obvious that the axis is hiding a bit of the plot resulting in non-square entries. The same is happening for the last column. Since I want the complete matrix to be seen - every entry with the same importance - is there any way this can be fixed?

imshow matplotlib figure
1 Answers

To me, this is just a visualisation issue. If I run your code and maximise the window, I do not see the overlapping you are talking about: enter image description here enter image description here

Otherwise, remove the spines but without hiding the ticks:

ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
ax.spines['bottom'].set_visible(False)
ax.spines['left'].set_visible(False)

enter image description here

EDIT

Reduce the thickness of the borders: [x.set_linewidth(0.3) for x in ax.spines.values()]

The following is the exported image:

enter image description here

With 0.2 the exported image looks like this: enter image description here

user_149528560
Related