figure of imshow() is too small

106

I'm trying to visualize a numpy array using imshow() since it's similar to imagesc() in Matlab.

imshow(random.rand(8, 90), interpolation='nearest')

The resulting figure is very small at the center of the grey window, while most of the space is unoccupied. How can I set the parameters to make the figure larger? I tried figsize=(xx,xx) and it's not what I want. Thanks!

This question is tagged with python numpy matplotlib

~ Asked on 2012-05-10 19:31:35

The Best Answer is


158

If you don't give an aspect argument to imshow, it will use the value for image.aspect in your matplotlibrc. The default for this value in a new matplotlibrc is equal. So imshow will plot your array with equal aspect ratio.

If you don't need an equal aspect you can set aspect to auto

imshow(random.rand(8, 90), interpolation='nearest', aspect='auto')

which gives the following figure

imshow-auto

If you want an equal aspect ratio you have to adapt your figsize according to the aspect

fig, ax = subplots(figsize=(18, 2))
ax.imshow(random.rand(8, 90), interpolation='nearest')
tight_layout()

which gives you:

imshow-equal

~ Answered on 2012-05-11 06:05:24


43

That's strange, it definitely works for me:

from matplotlib import pyplot as plt

plt.figure(figsize = (20,2))
plt.imshow(random.rand(8, 90), interpolation='nearest')

I am using the "MacOSX" backend, btw.

~ Answered on 2012-05-10 20:17:23


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