Simplify code.

Co-authored-by: Thomas Robitaille <thomas.robitaille@gmail.com>

jdaviz/app.py

@@ -1935,7 +1935,7 @@ def set_data_visibility(self, viewer_reference, data_label, visible=True, replac
             viewer.add_data(data, percentile=95, color=viewer.color_cycler())
 
             # Specviz removes the data from collection in viewer.py if flux unit incompatible.
-            if data_label not in self.data_collection.labels:
+            if data_label not in self.data_collection:
                 return
 
             viewer.set_plot_axes()

jdaviz/configs/specviz/plugins/viewers.py

@@ -5,13 +5,14 @@
 from astropy import units as u
 from astropy.nddata import StdDevUncertainty, VarianceUncertainty, InverseVariance
 from echo import delay_callback
+from glue.config import data_translator
 from glue.core import BaseData
-from glue_astronomy.spectral_coordinates import SpectralCoordinates
+from glue.core.exceptions import IncompatibleAttribute
+from glue.core.units import UnitConverter
 from glue.core.subset import Subset
 from glue.core.subset_group import GroupedSubset
-from glue.config import data_translator
+from glue_astronomy.spectral_coordinates import SpectralCoordinates
 from glue_jupyter.bqplot.profile import BqplotProfileView
-from glue.core.exceptions import IncompatibleAttribute
 from matplotlib.colors import cnames
 from specutils import Spectrum1D
 
@@ -25,6 +26,7 @@
 
 __all__ = ['SpecvizProfileView']
 
+uc = UnitConverter()
 
 uncertainty_str_to_cls_mapping = {
     "std": StdDevUncertainty,
@@ -369,12 +371,10 @@ def add_data(self, data, color=None, alpha=None, **layer_state):
         if len(self.layers) == 0:
             reset_plot_axes = True
         else:
-            # Check if the new data flux unit is actually compatible since flux not linked
-            data_flux_unit = u.Unit(y_units)
-            viewer_flux_unit = u.Unit(self.state.y_display_unit)
-            wav = 1 * u.Unit(self.state.x_display_unit)
+            # Check if the new data flux unit is actually compatible since flux not linked.
             try:
-                (1 * data_flux_unit).to(viewer_flux_unit, u.spectral_density(wav))  # Error if incompatible  # noqa: E501
+                uc.to_unit(data, data.find_component_id("flux"), [1, 1],
+                           u.Unit(self.state.y_display_unit))  # Error if incompatible
             except Exception as err:
                 # Raising exception here introduces a dirty state that messes up next load_data
                 # but not raising exception also causes weird behavior unless we remove the data