Create NonUniformImage based on Numpy 2d array with custom cell width and height

Question

I'm trying to make a "heatmap" with Matplotlib of a 2d Numpy Array and found the NonUniformImage option here. Below is a simple single version. Unfortunately I'm not able to change the x without changing the y. The error that pyhton Propmpts is: Axes don't match array shape

Reproducible Example

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.image import NonUniformImage
from matplotlib import cm

x = np.arange(6)
y = np.arange(6)
z = x[:, np.newaxis].dot(y[:, np.newaxis].transpose())

fig, ax = plt.subplots()
im = NonUniformImage(ax, interpolation='nearest', extent=(0, len(x)-1, 0, len(y)-1))
im.set_data(x, y, z)
ax.images.append(im)
ax.set_xlim(0, len(x)-1)
ax.set_ylim(0, len(y)-1)

My goal is to plot a map based on a Numpy 2d array with 'custom Grid cells'. That means that I can assign x and y with irregular series (e.g. np.array([0.5,3,8,15,15.4]). I know the x and y that are assign represent the center of a cell so the last thing I would like to solve is that the plot is completely visible (if that is possible).

How can I make a image that has a different constraint (not square), with custom width and height depending on two lists?

When I run your code I get this image. Is this not what you want? Or do you get a different result? — ImportanceOfBeingErnest
– ImportanceOfBeingErnest, Commented May 8, 2019 at 22:55
No I got the same result but I can only create images with the same dimensions (e.g. 6x6, 8x8 or 21x21). I would like to make an image of 60 x 29 and have custom height and width depending on to lists. I changed the question to make it more clear. — Dylan_w
– Dylan_w, Commented May 9, 2019 at 7:30

ImportanceOfBeingErnest · Accepted Answer · 2019-05-09 11:51:01Z

1

I suppose you made a mistake defining z. Possibly what you're after is

x = np.arange(6)
y = np.arange(8)
z = x[np.newaxis,:] * y[:, np.newaxis]
print(z.shape)

such that the shape is (8,6).

answered May 9, 2019 at 11:51

ImportanceOfBeingErnest

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