Merge pull request #2190 from djhoese/bugfix-btthreshold-enh

Fix some enhancements producing dask arrays wrapped in dask arrays

satpy/enhancements/__init__.py

@@ -277,11 +277,6 @@ def _srgb_gamma(arr):
     return da.where(arr < 0.0031308, arr * 12.92, 1.055 * arr ** 0.41666 - 0.055)
 
 
-def _lookup_delayed(luts, band_data):
-    # can't use luts.__getitem__ for some reason
-    return luts[band_data]
-
-
 def lookup(img, **kwargs):
     """Assign values to channels based on a table."""
     luts = np.array(kwargs['luts'], dtype=np.float32) / 255.0
@@ -295,11 +290,7 @@ def _lookup_table(band_data, luts=None, index=-1):
     # NaN/null values will become 0
     lut = luts[:, index] if len(luts.shape) == 2 else luts
     band_data = band_data.clip(0, lut.size - 1).astype(np.uint8)
-
-    new_delay = dask.delayed(_lookup_delayed)(lut, band_data)
-    new_data = da.from_delayed(new_delay, shape=band_data.shape,
-                               dtype=luts.dtype)
-    return new_data
+    return lut[band_data]
 
 
 def colorize(img, **kwargs):
@@ -596,6 +587,6 @@ def btemp_threshold(img, min_in, max_in, threshold, threshold_out=None, **kwargs
 @using_map_blocks
 def _bt_threshold(band_data, threshold, high_coeffs, low_coeffs):
     # expects dask array to be passed
-    return da.where(band_data >= threshold,
+    return np.where(band_data >= threshold,
                     high_coeffs.offset - high_coeffs.factor * band_data,
                     low_coeffs.offset - low_coeffs.factor * band_data)

satpy/tests/enhancement_tests/test_enhancements.py

@@ -44,7 +44,12 @@ def run_and_check_enhancement(func, data, expected, **kwargs):
     new_keys = set(img.data.attrs.keys()) - {"enhancement_history"}
     assert old_keys == new_keys
 
-    np.testing.assert_allclose(img.data.values, expected, atol=1.e-6, rtol=0)
+    res_data_arr = img.data
+    assert isinstance(res_data_arr, xr.DataArray)
+    assert isinstance(res_data_arr.data, da.Array)
+    res_data = res_data_arr.data.compute()  # mimics what xrimage geotiff writing does
+    assert not isinstance(res_data, da.Array)
+    np.testing.assert_allclose(res_data, expected, atol=1.e-6, rtol=0)
 
 
 def identical_decorator(func):