Extracted constants to their own file.

Author: Hneuschmidt

efast/constants.py

@@ -0,0 +1,41 @@
+from enum import Enum, Flag
+
+
+class S3L2SYNCloudFlags(Flag):
+    """
+    Flag meanings are described in the SYNERGY Product Data Format Specification [1]
+    Table 23
+    """
+    CLOUD = 1
+    CLOUD_AMBIGUOUS = 1 << 1
+    CLOUD_MARGIN = 1 << 2
+    SNOW_ICE = 1 << 3
+
+class S3L2SYNClassificationAerosolFlags(Flag):
+    """
+    Flag meanings are described in the SYNERGY Product Data Format Specification [1]
+    Talble 19
+
+
+    [1] https://sentinels.copernicus.eu/documents/247904/1872824/S3IPF+PDS+006+-+i1r15+-+Product+Data+Format+Specification+-+SYNERGY_20221208.pdf/48f4eb8c-ca08-eca1-f8dd-bf00c438ea52?t=1683308328839
+    """
+    SYN_AOT_climato = 1 << 3
+    SYN_land = 1 << 4
+    SYN_no_olc = 1 << 5
+    SYN_no_sln = 1 
+    # TODO ...
+
+class S2L2ASCFlags(Enum):
+    NO_DATA = 0
+    SATURATED_OR_DEFECTIVE = 1
+    CAST_SHADOWS = 2
+    CLOUD_SHADOWS = 3
+    VEGETATION = 4
+    NOT_VEGETATED = 5
+    WATER = 6
+    UNCLASSIFIED = 7
+    CLOUD_MEDIUM_PROBABILITY = 8
+    CLOUD_HIGH_PROBABILITY = 9
+    THIN_CIRRUS = 10
+    SNOW_ICE = 11
+    

efast/openeo/preprocessing/s2.py

@@ -2,23 +2,38 @@
 
 import openeo
 
+from efast.constants import S2L2ASCFlags
+
 from . import extract_mask
 
 
-def extract_cloud_mask_s2(cube: openeo.DataCube) -> openeo.DataCube:
+def extract_cloud_mask(cube: openeo.DataCube) -> openeo.DataCube:
     return extract_mask(
         cube,
-        {"SCL": [0, 3, 7]},
+        {
+            "SCL": [
+                S2L2ASCFlags.NO_DATA.value,
+                S2L2ASCFlags.CLOUD_SHADOWS.value,
+                S2L2ASCFlags.UNCLASSIFIED.value,
+            ]
+        },
         operations={
-            ("SCL", 7): operator.gt,
+            ("SCL", 7): operator.gt, # consider flags higher than 7 as clouds
         },
     )
 
-def calculate_large_grid_cloud_mask(cube: openeo.DataCube, tolerance_percentage: float = 0.05, grid_side_length: int=300):
-    cloud_mask = extract_cloud_mask_s2(cube)
+
+def calculate_large_grid_cloud_mask(
+    cube: openeo.DataCube,
+    tolerance_percentage: float = 0.05,
+    grid_side_length: int = 300,
+):
+    cloud_mask = extract_cloud_mask(cube)
     # FIXME check also if there is negative or zero data, otherwise results will differ
-    
+
     # TODO this could better be resample_cube_spatial, because we are matching to a sentinel-3 cube
-    cloud_mask = cloud_mask * 1.0 # convert to float
-    cloud_mask_resampled = cloud_mask.resample_spatial(grid_side_length, method="average") # resample to sentinel-3 size
+    cloud_mask = cloud_mask * 1.0  # convert to float
+    cloud_mask_resampled = cloud_mask.resample_spatial(
+        grid_side_length, method="average"
+    )  # resample to sentinel-3 size
     return cloud_mask_resampled < tolerance_percentage