import matplotlib.pyplot as plt
import numpy as np

import pint
ureg = pint.UnitRegistry()
ureg.setup_matplotlib()

X, Y = np.meshgrid(np.linspace(-3, 3, 16), np.linspace(-3, 3, 16))
Z = (1 - X/2 + X**5 + Y**3) * np.exp(-X**2 - Y**2)
Z *= ureg.kg

fig, ax = plt.subplots()
ax.imshow(Z, vmin=1*ureg.kg, vmax=2*ureg.kg)
plt.show()

% python test.py
/Users/dstansby/github/matplotlib/lib/matplotlib/cbook.py:672: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
  x = np.array(x, subok=True, copy=copy)
/Users/dstansby/github/matplotlib/lib/matplotlib/image.py:452: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
  dv = np.float64(self.norm.vmax) - np.float64(self.norm.vmin)
/Users/dstansby/github/matplotlib/lib/matplotlib/image.py:453: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
  vmid = np.float64(self.norm.vmin) + dv / 2
/Users/dstansby/github/matplotlib/lib/matplotlib/image.py:482: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
  vrange = np.array([vmin, vmax], dtype=scaled_dtype)
Traceback (most recent call last):
  File "/Users/dstansby/mambaforge/envs/mpl/lib/python3.10/site-packages/pint/facets/plain/quantity.py", line 707, in __float__
    raise DimensionalityError(self._units, "dimensionless")
pint.errors.DimensionalityError: Cannot convert from 'kilogram' to 'dimensionless'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/backend_bases.py", line 1223, in _on_timer
    ret = func(*args, **kwargs)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/backends/backend_macosx.py", line 68, in callback_func
    callback()
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/backends/backend_macosx.py", line 88, in _draw_idle
    self.draw()
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/backends/backend_macosx.py", line 50, in draw
    super().draw()
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/backends/backend_agg.py", line 400, in draw
    self.figure.draw(self.renderer)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/artist.py", line 95, in draw_wrapper
    result = draw(artist, renderer, *args, **kwargs)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/artist.py", line 72, in draw_wrapper
    return draw(artist, renderer)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/figure.py", line 3116, in draw
    mimage._draw_list_compositing_images(
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/image.py", line 131, in _draw_list_compositing_images
    a.draw(renderer)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/artist.py", line 72, in draw_wrapper
    return draw(artist, renderer)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/axes/_base.py", line 3066, in draw
    mimage._draw_list_compositing_images(
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/image.py", line 131, in _draw_list_compositing_images
    a.draw(renderer)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/artist.py", line 72, in draw_wrapper
    return draw(artist, renderer)
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/image.py", line 641, in draw
    im, l, b, trans = self.make_image(
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/image.py", line 948, in make_image
    return self._make_image(self._A, bbox, transformed_bbox, clip,
  File "/Users/dstansby/github/matplotlib/lib/matplotlib/image.py", line 482, in _make_image
    vrange = np.array([vmin, vmax], dtype=scaled_dtype)
ValueError: setting an array element with a sequence.