image_range trait in declarative plotting interface doesn't accept arbitrary floating point values #3027
Description
What went wrong?
There's really two issues in one, but I didn't want to clog up the issue list. The two are related, and both seem to be small changes.
-
The
image_rangetrait forImagePlotin the declarative plotting interface doesn't accept arbitrary floating point values, only integer ranges. -
The
image_rangetrait acceptsmpl.Normalizeinstances, but setting anmpl.Normalizeinstance causes the plotting to blow up.
These are small changes and I'm more than happy to put up PR's to fix these, but wanted to run them by the team.
Operating System
MacOS
Version
1.4.1
Python Version
3.11.3
Code to Reproduce
ds = xr.open_dataset(get_test_data('narr_example.nc')).metpy.parse_cf().sel(time='1987-04-04T18:00:00', isobaric=500)
img = ImagePlot()
img.data = ds
img.field = 'Temperature'
# first issue:
img.image_range = (14.5, 25.5)
# second issue:
from matplotlib.colors import Normalize
img.image_range = Normalize(vmin=14.5, vmax=25.5)
panel = MapPanel()
panel.area = [-107, -93, 29, 41]
panel.projection = 'lcc'
panel.layers = ['states', 'coastline', 'borders']
panel.plots = [img]
pc = PanelContainer()
pc.size = (14, 18)
pc.panels = [panel]
pc.show()Errors, Traceback, and Logs
TraitError Traceback (most recent call last)
Cell In[5], line 4
2 img.data = ds
3 img.field = 'Temperature'
----> 4 img.image_range = (14.5, 25.5)
6 panel = MapPanel()
7 panel.area = [-107, -93, 29, 41]
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:526, in ValidationMixin.__setattr__(self, name, value)
524 allowlist.extend(self.trait_names())
525 if name in allowlist or name.startswith('_'):
--> 526 super().__setattr__(name, value)
527 else:
528 closest = get_close_matches(name, allowlist, n=1)
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/traitlets/traitlets.py:732, in TraitType.__set__(self, obj, value)
730 raise TraitError('The "%s" trait is read-only.' % self.name)
731 else:
--> 732 self.set(obj, value)
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/traitlets/traitlets.py:706, in TraitType.set(self, obj, value)
705 def set(self, obj, value):
--> 706 new_value = self._validate(obj, value)
707 try:
708 old_value = obj._trait_values[self.name]
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/traitlets/traitlets.py:738, in TraitType._validate(self, obj, value)
736 return value
737 if hasattr(self, "validate"):
--> 738 value = self.validate(obj, value)
739 if obj._cross_validation_lock is False:
740 value = self._cross_validate(obj, value)
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/traitlets/traitlets.py:2306, in Union.validate(self, obj, value)
2304 except TraitError:
2305 continue
-> 2306 self.error(obj, value)
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/traitlets/traitlets.py:844, in TraitType.error(self, obj, value, error, info)
838 else:
839 e = "The '{}' trait expected {}, not {}.".format(
840 self.name,
841 self.info(),
842 describe("the", value),
843 )
--> 844 raise TraitError(e)
TraitError: The 'image_range' trait of an ImagePlot instance expected a tuple or a Normalize, not the tuple (14.5, 25.5).Here's the traceback for the Normalize issue:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
Cell In[7], line 18
15 pc.size = (14, 18)
16 pc.panels = [panel]
---> 18 pc.show()
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:622, in PanelContainer.show(self)
620 def show(self):
621 """Show the constructed graphic on the screen."""
--> 622 self.draw()
623 plt.show()
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:609, in PanelContainer.draw(self)
607 for panel in self.panels:
608 with panel.hold_trait_notifications():
--> 609 panel.draw()
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:897, in MapPanel.draw(self)
895 for p in self.plots:
896 with p.hold_trait_notifications():
--> 897 p.draw()
899 # Add all of the maps
900 if len(self.layers) > len(self.layers_edgecolor):
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:1259, in PlotScalar.draw(self)
1257 if self._need_redraw:
1258 if getattr(self, 'handle', None) is None:
-> 1259 self._build()
1260 if getattr(self, 'colorbar', None) is not None:
1261 cbar = self.parent.ax.figure.colorbar(
1262 self.handle, orientation=self.colorbar, pad=0, aspect=50)
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:1383, in ImagePlot._build(self)
1377 kwargs['extent'] = (x_like[0], x_like[-1], y_like.min(), y_like.max())
1378 kwargs['origin'] = 'upper' if y_like[0] > y_like[-1] else 'lower'
1380 self.handle = self.parent.ax.imshow(
1381 imdata,
1382 cmap=self._cmap_obj,
-> 1383 norm=self._norm_obj,
1384 **kwargs
1385 )
File ~/miniconda3/envs/yt-env/lib/python3.11/site-packages/metpy/plots/declarative.py:1049, in Plots2D._norm_obj(self)
1042 @property
1043 def _norm_obj(self):
1044 """Return the normalization object.
1045
1046 Converts the tuple image range to a matplotlib normalization instance.
1047
1048 """
-> 1049 return plt.Normalize(*self.image_range)
TypeError: matplotlib.colors.Normalize() argument after * must be an iterable, not Normalize