GMS_object.get_subset_obj() now returns None in case the subset contains no data at all.

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

gms_preprocessing/model/gms_object.py

@@ -1277,9 +1277,11 @@ class GMS_object(object):
 
     def get_subset_obj(self, imBounds=None, mapBounds=None, mapBounds_prj=None, out_prj=None, logmsg=None,
                        progress=False, v=False):
-        # type: (tuple, tuple, str, str, str, bool, bool) -> GMS_object
-        """Returns a subset of the given GMS object, based on the given bounds coordinates.
-        Array attributes are clipped and relevant metadata keys are updated according to new extent.
+        # type: (tuple, tuple, str, str, str, bool, bool) -> Union[GMS_object, None]
+        """Return a subset of the given GMS object, based on the given bounds coordinates.
+
+        Array attributes are clipped and relevant metadata keys are updated according to new extent. In case the subset
+        does not contain any data but only no-data values, None is returned.
 
         :param imBounds:        <tuple> tuple of image coordinates in the form (xmin,xmax,ymin,ymax)
         :param mapBounds:       <tuple> tuple of map coordinates in the form (xmin,xmax,ymin,ymax)
@@ -1347,6 +1349,12 @@ class GMS_object(object):
 
             # update array-related attributes of sub_GMS_obj
             if arrname == 'arr':
+                # return None in case the subset object contains only nodata
+                if subArr.min() == subArr.max() and \
+                   np.std(subArr) == 0 and \
+                   np.unique(subArr) == subArr.nodata:
+                    return None
+
                 sub_GMS_obj.MetaObj.map_info = geotransform2mapinfo(subArr.gt, subArr.prj)
                 sub_GMS_obj.MetaObj.projection = subArr.prj
                 sub_GMS_obj.MetaObj.rows, sub_GMS_obj.MetaObj.cols = subArr.arr.shape[:2]
@@ -1724,7 +1732,8 @@ class GMS_object(object):
             # validate that the MGRS tile truly contains data
             # -> this may not be the case if get_overlapping_MGRS_tiles() yielded invalid tiles due to inaccurate
             #    self.trueDataCornerLonLat
-            if True not in list(np.unique(tileObj.arr.mask_nodata)):
+            if tileObj is None or \
+               True not in list(np.unique(tileObj.arr.mask_nodata)):
                 self.logger.info("MGRS tile '%s' has not been skipped because it contains only no data values."
                                  % MGRS_tileID)
                 continue

gms_preprocessing/processing/pipeline.py

@@ -77,7 +77,7 @@ def L1A_map(dataset_dict):  # map (scene-wise parallelization)
 @EXC_H.log_uncaught_exceptions
 @update_proc_status
 def L1A_map_1(dataset_dict, block_size=None):  # map (scene-wise parallelization)
-    # type: (dict) -> List[L1A_P.L1A_object]
+    # type: (dict, tuple) -> List[L1A_P.L1A_object]
 
     L1A_obj = L1A_P.L1A_object(**dataset_dict)
     L1A_obj.block_at_system_overload(max_usage=CFG.critical_mem_usage)
@@ -87,8 +87,10 @@ def L1A_map_1(dataset_dict, block_size=None):  # map (scene-wise parallelization
     L1A_obj.apply_nodata_mask_to_ObjAttr('arr')  # nodata mask is automatically calculated
     L1A_obj.add_rasterInfo_to_MetaObj()
     L1A_obj.reference_data('UTM')
-    tiles = list(L1A_obj.to_tiles(
-        block_size if block_size else CFG.tiling_block_size_XY))  # cut (block-wise parallelization)
+    tiles = [tile for tile in
+             # cut (block-wise parallelization)
+             L1A_obj.to_tiles(blocksize=block_size if block_size else CFG.tiling_block_size_XY)
+             if tile is not None]    # None is returned in case the tile contains no data at all
     return tiles
 
 
@@ -182,7 +184,7 @@ def L1C_map(L1B_objs):
 @EXC_H.log_uncaught_exceptions
 @update_proc_status
 def L2A_map(L1C_objs, block_size=None, return_tiles=True):
-    # type: (Union[List[L1C_P.L1C_object], Tuple[L1C_P.L1C_object]]) -> Union[List[L2A_P.L2A_object], L2A_P.L2A_object]
+    # type: (Union[List[L1C_P.L1C_object], Tuple[L1C_P.L1C_object]], tuple, bool) -> Union[List[L2A_P.L2A_object], L2A_P.L2A_object]  # noqa
     """Geometric homogenization.
 
     Performs correction of geometric displacements, resampling to target grid of the usecase and merges multiple
@@ -229,6 +231,7 @@ def L2A_map(L1C_objs, block_size=None, return_tiles=True):
 
     if return_tiles:
         L2A_tiles = list(L2A_obj.to_tiles(blocksize=block_size if block_size else CFG.tiling_block_size_XY))
+        L2A_tiles = [i for i in L2A_tiles if i is not None]  # None is returned in case the tile contains no data at all
         [L2A_tile.record_mem_usage() for L2A_tile in L2A_tiles]
         return L2A_tiles
     else: