Added a validation to reject images that only contain nodata values +…

… test.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>

HISTORY.rst

@@ -2,6 +2,12 @@
 History
 =======
 
+1.7.7 (coming soon)
+-------------------
+
+* Added a validation to reject images that only contain nodata values.
+
+
 1.7.6 (2022-01-31)
 ------------------
 

arosics/CoReg.py

@@ -98,6 +98,12 @@ def __init__(self,
             % (self.imName, self.bands, 'bands' if self.bands > 1 else
                'band', 'between 1 and ' if self.bands > 1 else '', self.bands, self.band4match)
 
+        # compute nodata mask and validate that it is not completely filled with nodata
+        self.calc_mask_nodata(fromBand=self.band4match)  # this avoids that all bands have to be read
+
+        if np.std(self.mask_nodata) == 0 and np.mean(self.mask_nodata) == 0:
+            raise RuntimeError(f'The {self.imName} passed to AROSICS only contains nodata values.')
+
         # set footprint_poly
         given_footprint_poly = CoReg_params['footprint_poly_%s' % ('ref' if imID == 'ref' else 'tgt')]
         given_corner_coord = CoReg_params['data_corners_%s' % ('ref' if imID == 'ref' else 'tgt')]
@@ -114,8 +120,6 @@ def __init__(self,
             if not CoReg_params['q']:
                 print('Calculating footprint polygon and actual data corner coordinates for %s...' % self.imName)
 
-            self.calc_mask_nodata(fromBand=self.band4match)  # this avoids that all bands have to be read
-
             with warnings.catch_warnings(record=True) as w:
                 _ = self.footprint_poly  # execute getter
 

tests/test_COREG.py

@@ -63,6 +63,22 @@ def test_coreg_init_from_inMem_GeoArray(self):
         # get instance of COREG_LOCAL object
         self.CRL = COREG(self.ref_gA, self.tgt_gA, **self.coreg_kwargs)
 
+    def test_empty_image(self):
+        # get GeoArray instances
+        self.ref_gA = GeoArray(self.ref_path)
+        self.tgt_gA = GeoArray(self.tgt_path)
+
+        # assure the raster data are in-memory
+        self.ref_gA.to_mem()
+        self.tgt_gA.to_mem()
+
+        # fill the reference image with nodata
+        self.ref_gA[:] = self.ref_gA.nodata
+
+        # get instance of COREG_LOCAL object
+        with self.assertRaises(RuntimeError, msg='.contains only nodata.'):
+            COREG(self.ref_gA, self.tgt_gA, **self.coreg_kwargs)
+
 
 class CompleteWorkflow_INTER1_S2A_S2A(unittest.TestCase):
     """Test case for the complete workflow of global co-registration based on two Sentinel-2 datasets, one with