Trying to use imshow() with a Quantity and LogNorm, and then trying to draw a colorbar doesn't work. I suspect this needs to be fixed in matplotlib, but thought I would open it here too just in case.
A simple example is:
import astropy.units as u
import matplotlib.colors as mcolor
import matplotlib.pyplot as plt
import numpy as np
data = np.random.rand(2, 2) * u.m
fig, ax = plt.subplots()
im = ax.imshow(data, norm=mcolor.LogNorm())
fig.colorbar(im)
plt.show()
which fails with
Traceback (most recent call last):
File "/Users/dstansby/github/matplotlib/examples/units/units_imshow.py", line 9, in <module>
im = ax.imshow(data, norm=mcolor.LogNorm())
File "/Users/dstansby/github/matplotlib/lib/matplotlib/__init__.py", line 1348, in inner
return func(ax, *map(sanitize_sequence, args), **kwargs)
File "/Users/dstansby/github/matplotlib/lib/matplotlib/axes/_axes.py", line 5591, in imshow
im._scale_norm(norm, vmin, vmax)
File "/Users/dstansby/github/matplotlib/lib/matplotlib/cm.py", line 291, in _scale_norm
self.autoscale_None()
File "/Users/dstansby/github/matplotlib/lib/matplotlib/cm.py", line 476, in autoscale_None
self.norm.autoscale_None(self._A)
File "/Users/dstansby/github/matplotlib/lib/matplotlib/colors.py", line 1522, in autoscale_None
super().autoscale_None(np.ma.masked_less_equal(A, 0, copy=False))
File "/Users/dstansby/miniconda3/envs/dev/lib/python3.9/site-packages/numpy/ma/core.py", line 2043, in masked_less_equal
return masked_where(less_equal(x, value), x, copy=copy)
File "/Users/dstansby/miniconda3/envs/dev/lib/python3.9/site-packages/numpy/ma/core.py", line 1932, in masked_where
cond = mask_or(cond, a._mask)
File "/Users/dstansby/miniconda3/envs/dev/lib/python3.9/site-packages/numpy/ma/core.py", line 1742, in mask_or
return make_mask(m1, copy=copy, shrink=shrink, dtype=dtype)
File "/Users/dstansby/miniconda3/envs/dev/lib/python3.9/site-packages/numpy/ma/core.py", line 1635, in make_mask
result = _shrink_mask(result)
File "/Users/dstansby/miniconda3/envs/dev/lib/python3.9/site-packages/numpy/ma/core.py", line 1544, in _shrink_mask
if m.dtype.names is None and not m.any():
File "/Users/dstansby/github/astropy/astropy/units/quantity.py", line 1645, in any
raise TypeError("cannot evaluate truth value of quantities. "
TypeError: cannot evaluate truth value of quantities. Evaluate array with q.value.any(...)This is present on both (Matplotlib master, astropy master) and (Matplotlib 3.3.4, astropy 4.2) with the same error message.
Trying to use
imshow()with aQuantityandLogNorm, and then trying to draw a colorbar doesn't work. I suspect this needs to be fixed in matplotlib, but thought I would open it here too just in case.A simple example is:
which fails with
This is present on both (Matplotlib master, astropy master) and (Matplotlib 3.3.4, astropy 4.2) with the same error message.