Support OLCI Collection 4 (v4.01) L2 water processing baseline

CHANGELOG.md

@@ -20,6 +20,11 @@ number as needed.
 
 ### Fixed
 
+- Support the OLCI Collection 4 (v4.01) level 2 water processing baseline:
+  data objects absent from a manifest (such as the OC4Me chlorophyll product
+  `chlOc4meData`, removed in Collection 4) are skipped instead of raising a
+  `RuntimeError`, and the new `chlor_a`, `fluorescence`, and `iop_lsd`
+  products are turned into assets when present
 - Use correct EO Extension attribute names and units ([#13](https://github.com/stactools-packages/sentinel3/pull/15))
 - Use un-stripped `instance_id` to check for strip granules and apply geometry
   fix ([#19](https://github.com/stactools-packages/sentinel3/pull/19))

src/stactools/sentinel3/constants.py

@@ -730,6 +730,65 @@
     "wqsfData",
 ]
 
+# Additional data objects introduced by the OLCI Collection 4 (v4.01)
+# processing baseline for level 2 water products. The OC4Me chlorophyll
+# product (chl_oc4me.nc / chlOc4meData) was replaced by chlor_a.nc, and the
+# fluorescence (fluorescence.nc) and inherent optical properties (iop_lsd.nc)
+# products were added. See:
+# https://user.eumetsat.int/news-events/news/update-to-sentinel-3-olci-level-2-water-processing
+OLCI_L2_WATER_ASSET_KEYS_C4 = [
+    "chlor_aData",
+    "fluoData",
+    "iopLsdData",
+]
+
+# Maps each OLCI L2 water data object ID to the OLCI bands it is derived from.
+# Data objects without an entry here (annotation files, and the Collection 4
+# chlor_a/fluorescence/iop_lsd products) carry no eo:bands.
+OLCI_L2_WATER_BAND_KEYS = {
+    "chlNnData": [
+        "Oa01",
+        "Oa02",
+        "Oa03",
+        "Oa04",
+        "Oa05",
+        "Oa06",
+        "Oa07",
+        "Oa08",
+        "Oa09",
+        "Oa10",
+        "Oa11",
+        "Oa12",
+        "Oa16",
+        "Oa17",
+        "Oa18",
+        "Oa21",
+    ],
+    "tsmNnData": [
+        "Oa01",
+        "Oa02",
+        "Oa03",
+        "Oa04",
+        "Oa05",
+        "Oa06",
+        "Oa07",
+        "Oa08",
+        "Oa09",
+        "Oa10",
+        "Oa11",
+        "Oa12",
+        "Oa16",
+        "Oa17",
+        "Oa18",
+        "Oa21",
+    ],
+    "chlOc4meData": ["Oa03", "Oa04", "Oa05", "Oa06"],
+    "iopNnData": ["Oa01", "Oa12", "Oa16", "Oa17", "Oa21"],
+    "iwvData": ["Oa18", "Oa19"],
+    "trspData": ["Oa04", "Oa06"],
+    "wAerData": ["Oa05", "Oa06", "Oa17"],
+}
+
 SLSTR_L1_ASSET_KEYS = [
     "SLSTR_S1_RAD_AN_Data",
     "SLSTR_S2_RAD_AN_Data",

src/stactools/sentinel3/metadata_links.py

@@ -559,55 +559,25 @@ def strip_prefix(prefix: str, content: str) -> str:
                     asset_identifier_list.append(asset_key)
                     asset_list.append(asset_obj)
             elif "_WFR_" in product_type:
-                asset_key_list = constants.OLCI_L2_WATER_ASSET_KEYS
-                for asset_key in asset_key_list:
-                    if asset_key == "chlNnData" or asset_key == "tsmNnData":
-                        band_key_list = [
-                            "Oa01",
-                            "Oa02",
-                            "Oa03",
-                            "Oa04",
-                            "Oa05",
-                            "Oa06",
-                            "Oa07",
-                            "Oa08",
-                            "Oa09",
-                            "Oa10",
-                            "Oa11",
-                            "Oa12",
-                            "Oa16",
-                            "Oa17",
-                            "Oa18",
-                            "Oa21",
-                        ]
-                    elif asset_key == "chlOc4meData":
-                        band_key_list = ["Oa03", "Oa04", "Oa05", "Oa06"]
-                    elif asset_key == "iopNnData":
-                        band_key_list = [
-                            "Oa01",
-                            "Oa12",
-                            "Oa16",
-                            "Oa17",
-                            "Oa21",
-                        ]
-                    elif asset_key == "iwvData":
-                        band_key_list = [
-                            "Oa18",
-                            "Oa19",
-                        ]
-                    elif asset_key == "parData":
-                        band_key_list = []
-                    elif asset_key == "trspData":
-                        band_key_list = ["Oa04", "Oa06"]
-                    elif asset_key == "wAerData":
-                        band_key_list = ["Oa05", "Oa06", "Oa17"]
-                    elif any(
-                        asset_key == key
-                        for key in constants.OLCI_L2_WATER_ASSET_KEYS[-7:]
+                # Iterate over both the legacy water keys and the Collection 4
+                # (v4.01) additions. Data objects that are not present in this
+                # particular manifest are skipped, so the same code handles
+                # both the old and new processing baselines.
+                present_asset_keys = []
+                for asset_key in (
+                    constants.OLCI_L2_WATER_ASSET_KEYS
+                    + constants.OLCI_L2_WATER_ASSET_KEYS_C4
+                ):
+                    if len(manifest.findall(f".//dataObject[@ID='{asset_key}']")) == 0:
+                        continue
+                    if asset_key in constants.OLCI_L2_WATER_BAND_KEYS:
+                        band_key_list = constants.OLCI_L2_WATER_BAND_KEYS[asset_key]
+                    elif asset_key.startswith("Oa") and asset_key.endswith(
+                        "_reflectanceData"
                     ):
-                        band_key_list = []
-                    else:
                         band_key_list = [asset_key[:4]]
+                    else:
+                        band_key_list = []
                     asset_location = self.read_href(
                         f".//dataObject[@ID='{asset_key}']//fileLocation"
                     )
@@ -653,8 +623,12 @@ def strip_prefix(prefix: str, content: str) -> str:
                             roles=["data"],
                             extra_fields={"s3:spatial_resolution": asset_resolution},
                         )
+                    present_asset_keys.append(asset_key)
                     asset_identifier_list.append(asset_key)
                     asset_list.append(asset_obj)
+                # Return only the keys actually present in this manifest so the
+                # asset keys stay aligned with asset_identifier_list/asset_list.
+                asset_key_list = present_asset_keys
         elif instrument_bands == constants.SENTINEL_SLSTR_BANDS:
             if "SL_1_" in product_type:
                 asset_key_list = constants.SLSTR_L1_ASSET_KEYS