Fix BackgroundCompositor not retaining input metadata

satpy/composites/__init__.py

@@ -391,7 +391,7 @@ def __call__(self, projectables, **info):
             # we were not given SZA, generate SZA then calculate cos(SZA)
             from pyorbital.astronomy import cos_zen
             LOG.debug("Computing sun zenith angles.")
-            lons, lats = vis.attrs["area"].get_lonlats_dask(CHUNK_SIZE)
+            lons, lats = vis.attrs["area"].get_lonlats(chunks=CHUNK_SIZE)
 
             coords = {}
             if 'y' in vis.coords and 'x' in vis.coords:
@@ -512,9 +512,7 @@ def get_angles(self, vis):
         from pyorbital.astronomy import get_alt_az, sun_zenith_angle
         from pyorbital.orbital import get_observer_look
 
-        lons, lats = vis.attrs['area'].get_lonlats_dask(
-            chunks=vis.data.chunks)
-
+        lons, lats = vis.attrs['area'].get_lonlats(chunks=vis.data.chunks)
         sunalt, suna = get_alt_az(vis.attrs['start_time'], lons, lats)
         suna = np.rad2deg(suna)
         sunz = sun_zenith_angle(vis.attrs['start_time'], lons, lats)
@@ -635,7 +633,7 @@ def _get_reflectance(self, projectables, optional_datasets):
         if sun_zenith is None:
             if sun_zenith_angle is None:
                 raise ImportError("No module named pyorbital.astronomy")
-            lons, lats = _nir.attrs["area"].get_lonlats_dask(CHUNK_SIZE)
+            lons, lats = _nir.attrs["area"].get_lonlats(chunks=CHUNK_SIZE)
             sun_zenith = sun_zenith_angle(_nir.attrs['start_time'], lons, lats)
 
         return self._refl3x.reflectance_from_tbs(sun_zenith, _nir, _tb11, tb_ir_co2=tb13_4)
@@ -682,7 +680,7 @@ def __call__(self, projectables, optional_datasets=None, **info):
             satz = optional_datasets[0]
         else:
             from pyorbital.orbital import get_observer_look
-            lons, lats = band.attrs['area'].get_lonlats_dask(CHUNK_SIZE)
+            lons, lats = band.attrs['area'].get_lonlats(chunks=CHUNK_SIZE)
             sat_lon, sat_lat, sat_alt = get_satpos(band)
             try:
                 dummy, satel = get_observer_look(sat_lon,
@@ -787,10 +785,22 @@ def __init__(self, name, common_channel_mask=True, **kwargs):
         Args:
             common_channel_mask (bool): If True, mask all the channels with
                 a mask that combines all the invalid areas of the given data.
+
         """
         self.common_channel_mask = common_channel_mask
         super(GenericCompositor, self).__init__(name, **kwargs)
 
+    @classmethod
+    def infer_mode(cls, data_arr):
+        """Guess at the mode for a particular DataArray."""
+        if 'mode' in data_arr.attrs:
+            return data_arr.attrs['mode']
+        if 'bands' not in data_arr.dims:
+            return cls.modes[1]
+        if 'bands' in data_arr.coords and isinstance(data_arr.coords['bands'][0], str):
+            return ''.join(data_arr.coords['bands'].values)
+        return cls.modes[data_arr.sizes['bands']]
+
     def _concat_datasets(self, projectables, mode):
         try:
             data = xr.concat(projectables, 'bands', coords='minimal')
@@ -866,7 +876,7 @@ class FillingCompositor(GenericCompositor):
 
     def __call__(self, projectables, nonprojectables=None, **info):
         """Generate the composite."""
-        projectables = self.check_areas(projectables)
+        projectables = self.match_data_arrays(projectables)
         projectables[1] = projectables[1].fillna(projectables[0])
         projectables[2] = projectables[2].fillna(projectables[0])
         projectables[3] = projectables[3].fillna(projectables[0])
@@ -878,7 +888,7 @@ class Filler(GenericCompositor):
 
     def __call__(self, projectables, nonprojectables=None, **info):
         """Generate the composite."""
-        projectables = self.check_areas(projectables)
+        projectables = self.match_data_arrays(projectables)
         filled_projectable = projectables[0].fillna(projectables[1])
         return super(Filler, self).__call__([filled_projectable], **info)
 
@@ -1000,6 +1010,7 @@ def __init__(self, name, lim_low=85., lim_high=95., **kwargs):
                              blending of the given channels
             lim_high (float): upper limit of Sun zenith angle for the
                              blending of the given channels
+
         """
         self.lim_low = lim_low
         self.lim_high = lim_high
@@ -1024,7 +1035,7 @@ def __call__(self, projectables, **kwargs):
                 chunks = day_data.sel(bands=day_data['bands'][0]).chunks
             except KeyError:
                 chunks = day_data.chunks
-            lons, lats = day_data.attrs["area"].get_lonlats_dask(chunks)
+            lons, lats = day_data.attrs["area"].get_lonlats(chunks=chunks)
             coszen = xr.DataArray(cos_zen(day_data.attrs["start_time"],
                                           lons, lats),
                                   dims=['y', 'x'],
@@ -1069,7 +1080,10 @@ def enhance2dataset(dset):
     # Clip image data to interval [0.0, 1.0]
     data = img.data.clip(0.0, 1.0)
     data.attrs = attrs
-
+    # remove 'mode' if it is specified since it may have been updated
+    data.attrs.pop('mode', None)
+    # update mode since it may have changed (colorized/palettize)
+    data.attrs['mode'] = GenericCompositor.infer_mode(data)
     return data
 
 
@@ -1198,7 +1212,7 @@ class RatioSharpenedRGB(GenericCompositor):
     footprint. Note that the input data to this compositor must already be
     resampled so all data arrays are the same shape.
 
-    Example:
+    Example::
 
         R_lo -  1000m resolution - shape=(2000, 2000)
         G - 1000m resolution - shape=(2000, 2000)
@@ -1319,7 +1333,7 @@ def _mean4(data, offset=(0, 0), block_id=None):
 class SelfSharpenedRGB(RatioSharpenedRGB):
     """Sharpen RGB with ratio of a band with a strided-version of itself.
 
-    Example:
+    Example::
 
         R -  500m resolution - shape=(4000, 4000)
         G - 1000m resolution - shape=(2000, 2000)
@@ -1428,6 +1442,7 @@ def __init__(self, name, filename=None, area=None, **kwargs):
             filename (str): Filename of the image to load
             area (str): Name of area definition for the image.  Optional
                         for images with built-in area definitions (geotiff)
+
         """
         if filename is None:
             raise ValueError("No image configured for static image compositor")
@@ -1479,7 +1494,7 @@ class BackgroundCompositor(GenericCompositor):
 
     def __call__(self, projectables, *args, **kwargs):
         """Call the compositor."""
-        projectables = self.check_areas(projectables)
+        projectables = self.match_data_arrays(projectables)
 
         # Get enhanced datasets
         foreground = enhance2dataset(projectables[0])
@@ -1494,9 +1509,12 @@ def __call__(self, projectables, *args, **kwargs):
 
         # Get merged metadata
         attrs = combine_metadata(foreground, background)
+        if attrs.get('sensor') is None:
+            # sensor can be a set
+            attrs['sensor'] = self._get_sensors(projectables)
 
         # Stack the images
-        if 'A' in foreground.mode:
+        if 'A' in foreground.attrs['mode']:
             # Use alpha channel as weight and blend the two composites
             alpha = foreground.sel(bands='A')
             data = []
@@ -1514,6 +1532,5 @@ def __call__(self, projectables, *args, **kwargs):
             data = [data.sel(bands=b) for b in data['bands']]
 
         res = super(BackgroundCompositor, self).__call__(data, **kwargs)
-        res.attrs['area'] = attrs['area']
-
+        res.attrs.update(attrs)
         return res

satpy/etc/composites/seviri.yaml

@@ -313,7 +313,7 @@ composites:
     standard_name: overview
 
   colorized_ir_clouds:
-    compositor: !!python/name:satpy.composites.GenericCompositor
+    compositor: !!python/name:satpy.composites.SingleBandCompositor
     prerequisites:
       - name: 'IR_108'
     standard_name: colorized_ir_clouds

satpy/tests/compositor_tests/__init__.py

@@ -381,7 +381,7 @@ def setUp(self):
         lons = da.from_array(lons, lons.shape)
         lats = np.array([[40., 41.], [42., 43.]])
         lats = da.from_array(lats, lats.shape)
-        my_area.get_lonlats_dask.return_value = (lons, lats)
+        my_area.get_lonlats.return_value = (lons, lats)
         self.data_a.attrs['area'] = my_area
         self.data_b.attrs['area'] = my_area
         # not used except to check that it matches the data arrays
@@ -545,10 +545,10 @@ def test_compositor(self, calculator, apply_modifier_info, sza):
         nir.attrs['platform_name'] = platform
         nir.attrs['sensor'] = sensor
         nir.attrs['name'] = chan_name
-        get_lonlats_dask = mock.MagicMock()
+        get_lonlats = mock.MagicMock()
         lons, lats = 1, 2
-        get_lonlats_dask.return_value = (lons, lats)
-        nir.attrs['area'] = mock.MagicMock(get_lonlats_dask=get_lonlats_dask)
+        get_lonlats.return_value = (lons, lats)
+        nir.attrs['area'] = mock.MagicMock(get_lonlats=get_lonlats)
         start_time = 1
         nir.attrs['start_time'] = start_time
         ir_arr = 100 * np.random.random((2, 2))
@@ -574,7 +574,7 @@ def test_compositor(self, calculator, apply_modifier_info, sza):
         refl_from_tbs.reset_mock()
 
         res = comp([nir, ir_], optional_datasets=[], **info)
-        get_lonlats_dask.assert_called()
+        get_lonlats.assert_called()
         sza.assert_called_with(start_time, lons, lats)
         refl_from_tbs.assert_called_with(sunz2, nir, ir_, tb_ir_co2=None)
         refl_from_tbs.reset_mock()
@@ -831,7 +831,7 @@ def test_call(self):
         self.assertTrue('modifiers' not in res.attrs)
         self.assertIsNone(res.attrs['wavelength'])
         self.assertEqual(res.attrs['mode'], 'LA')
-        self.assertEquals(res.attrs['resolution'], 333)
+        self.assertEqual(res.attrs['resolution'], 333)
 
 
 class TestAddBands(unittest.TestCase):
@@ -949,28 +949,23 @@ def load(self, arg):
         self.assertEqual(res.attrs['area'].area_id, 'euro4')
 
 
+def _enhance2dataset(dataset):
+    """Mock the enhance2dataset to return the original data."""
+    return dataset
+
+
 class TestBackgroundCompositor(unittest.TestCase):
     """Test case for the background compositor."""
 
-    @mock.patch('satpy.composites.combine_metadata')
-    @mock.patch('satpy.composites.add_bands')
-    @mock.patch('satpy.composites.enhance2dataset')
-    @mock.patch('satpy.composites.BackgroundCompositor.check_areas')
-    def test_call(self, check_areas, e2d, add_bands, combine_metadata):
+    @mock.patch('satpy.composites.enhance2dataset', _enhance2dataset)
+    def test_call(self):
         """Test the background compositing."""
         from satpy.composites import BackgroundCompositor
         import numpy as np
-
-        def check_areas_side_effect(projectables):
-            return projectables
-
-        check_areas.side_effect = check_areas_side_effect
         comp = BackgroundCompositor("name")
 
         # L mode images
         attrs = {'mode': 'L', 'area': 'foo'}
-        combine_metadata.return_value = attrs
-
         foreground = xr.DataArray(np.array([[[1., 0.5],
                                              [0., np.nan]]]),
                                   dims=('bands', 'y', 'x'),
@@ -979,16 +974,13 @@ def check_areas_side_effect(projectables):
         background = xr.DataArray(np.ones((1, 2, 2)), dims=('bands', 'y', 'x'),
                                   coords={'bands': [c for c in attrs['mode']]},
                                   attrs=attrs)
-        add_bands.side_effect = [foreground, background]
-        res = comp([0, 1])
+        res = comp([foreground, background])
         self.assertEqual(res.attrs['area'], 'foo')
         self.assertTrue(np.all(res == np.array([[1., 0.5], [0., 1.]])))
-        self.assertEqual(res.mode, 'L')
+        self.assertEqual(res.attrs['mode'], 'L')
 
         # LA mode images
         attrs = {'mode': 'LA', 'area': 'foo'}
-        combine_metadata.return_value = attrs
-
         foreground = xr.DataArray(np.array([[[1., 0.5],
                                              [0., np.nan]],
                                             [[0.5, 0.5],
@@ -999,15 +991,12 @@ def check_areas_side_effect(projectables):
         background = xr.DataArray(np.ones((2, 2, 2)), dims=('bands', 'y', 'x'),
                                   coords={'bands': [c for c in attrs['mode']]},
                                   attrs=attrs)
-        add_bands.side_effect = [foreground, background]
-        res = comp([0, 1])
+        res = comp([foreground, background])
         self.assertTrue(np.all(res == np.array([[1., 0.75], [0.5, 1.]])))
-        self.assertEqual(res.mode, 'L')
+        self.assertEqual(res.attrs['mode'], 'LA')
 
         # RGB mode images
         attrs = {'mode': 'RGB', 'area': 'foo'}
-        combine_metadata.return_value = attrs
-
         foreground = xr.DataArray(np.array([[[1., 0.5],
                                              [0., np.nan]],
                                             [[1., 0.5],
@@ -1021,17 +1010,14 @@ def check_areas_side_effect(projectables):
                                   coords={'bands': [c for c in attrs['mode']]},
                                   attrs=attrs)
 
-        add_bands.side_effect = [foreground, background]
-        res = comp([0, 1])
+        res = comp([foreground, background])
         self.assertTrue(np.all(res == np.array([[[1., 0.5], [0., 1.]],
                                                 [[1., 0.5], [0., 1.]],
                                                 [[1., 0.5], [0., 1.]]])))
-        self.assertEqual(res.mode, 'RGB')
+        self.assertEqual(res.attrs['mode'], 'RGB')
 
         # RGBA mode images
         attrs = {'mode': 'RGBA', 'area': 'foo'}
-        combine_metadata.return_value = attrs
-
         foreground = xr.DataArray(np.array([[[1., 0.5],
                                              [0., np.nan]],
                                             [[1., 0.5],
@@ -1047,12 +1033,36 @@ def check_areas_side_effect(projectables):
                                   coords={'bands': [c for c in attrs['mode']]},
                                   attrs=attrs)
 
-        add_bands.side_effect = [foreground, background]
-        res = comp([0, 1])
+        res = comp([foreground, background])
         self.assertTrue(np.all(res == np.array([[[1., 0.75], [0.5, 1.]],
                                                 [[1., 0.75], [0.5, 1.]],
                                                 [[1., 0.75], [0.5, 1.]]])))
-        self.assertEqual(res.mode, 'RGB')
+        self.assertEqual(res.attrs['mode'], 'RGBA')
+
+    @mock.patch('satpy.composites.enhance2dataset', _enhance2dataset)
+    def test_multiple_sensors(self):
+        """Test the background compositing from multiple sensor data."""
+        from satpy.composites import BackgroundCompositor
+        import numpy as np
+        comp = BackgroundCompositor("name")
+
+        # L mode images
+        attrs = {'mode': 'L', 'area': 'foo'}
+        foreground = xr.DataArray(np.array([[[1., 0.5],
+                                             [0., np.nan]]]),
+                                  dims=('bands', 'y', 'x'),
+                                  coords={'bands': [c for c in attrs['mode']]},
+                                  attrs=attrs.copy())
+        foreground.attrs['sensor'] = 'abi'
+        background = xr.DataArray(np.ones((1, 2, 2)), dims=('bands', 'y', 'x'),
+                                  coords={'bands': [c for c in attrs['mode']]},
+                                  attrs=attrs.copy())
+        background.attrs['sensor'] = 'glm'
+        res = comp([foreground, background])
+        self.assertEqual(res.attrs['area'], 'foo')
+        self.assertTrue(np.all(res == np.array([[1., 0.5], [0., 1.]])))
+        self.assertEqual(res.attrs['mode'], 'L')
+        self.assertEqual(res.attrs['sensor'], {'abi', 'glm'})
 
 
 def suite():