Merge pull request #1524 from dopplershift/plot-obs-level

Fixing handling of level in PlotObs

src/metpy/plots/declarative.py

@@ -1317,7 +1317,7 @@ class PlotObs(HasTraits):
     parent = Instance(Panel)
     _need_redraw = Bool(default_value=True)
 
-    level = Union([Int(allow_none=True), Instance(units.Quantity)])
+    level = Union([Int(allow_none=True), Instance(units.Quantity)], default_value=None)
     level.__doc__ = """The level of the field to be plotted.
 
     This is a value with units to choose the desired plot level. For example, selecting the
@@ -1463,7 +1463,8 @@ def obsdata(self):
 
             # Subset for a particular level if given
             if self.level is not None:
-                data = data[data.pressure == self.level.m]
+                mag = getattr(self.level, 'magnitude', self.level)
+                data = data[data.pressure == mag]
 
             # Subset for our particular time
             if self.time is not None:

tests/plots/test_declarative.py

@@ -553,7 +553,6 @@ def test_plotobs_subset_default_nolevel(sample_obs):
     """Test PlotObs subsetting with minimal config."""
     obs = PlotObs()
     obs.data = sample_obs
-    obs.level = None
 
     truth = pd.DataFrame([('2020-08-06 13:00', 'KDEN', 500, 7, 15),
                           ('2020-08-06 12:59', 'KOKC', 500, 8, 16)],
@@ -575,6 +574,19 @@ def test_plotobs_subset_level(sample_obs):
     pd.testing.assert_frame_equal(obs.obsdata, truth)
 
 
+def test_plotobs_subset_level_no_units(sample_obs):
+    """Test PlotObs subsetting based on unitless level."""
+    obs = PlotObs()
+    obs.data = sample_obs
+    obs.level = 1000
+
+    truth = pd.DataFrame([('2020-08-06 13:00', 'KDEN', 1000, 5, 13),
+                          ('2020-08-06 12:59', 'KOKC', 1000, 6, 14)],
+                         columns=['time', 'stid', 'pressure', 'temperature', 'dewpoint'],
+                         index=[4, 5])
+    pd.testing.assert_frame_equal(obs.obsdata, truth)
+
+
 def test_plotobs_subset_time(sample_obs):
     """Test PlotObs subsetting for a particular time."""
     obs = PlotObs()