Merge pull request #309 from gaoflow/fix-307-landsat-stac-nir08

FIX: Resolve Landsat STAC bands whose asset name differs from the common name (#307)

Author: remi-braun

CHANGES.md

@@ -3,6 +3,7 @@
 ## 0.24.1 (2026-mm-dd)
 
 - FIX: Fix subsetting complex SAR data with a window (cannot be done directly in the ESA SNAP Read Operator)
+- FIX: Fix `KeyError` when loading a Landsat Collection-2 band from a STAC item whose asset name differs from the STAC common name (e.g. `nir08` instead of `nir`) [#307](https://github.com/sertit/eoreader/issues/307)
 
 ## 0.24.0 (2026-05-05)
 

ci/on_push/test_stac_items.py

@@ -8,6 +8,7 @@
 from tempenv import tempenv
 
 from ci.scripts_utils import READER, compare, reduce_verbosity
+from eoreader.bands import NIR
 from eoreader.products import Product
 from eoreader.reader import Constellation
 
@@ -96,6 +97,24 @@ def test_l5_mpc():
     )
 
 
+def test_l9_l2_mpc_nir_asset():
+    """Resolving the NIR band of a Landsat C2 L2 MPC item must not raise (#307).
+
+    These items expose the NIR band under the versioned STAC asset name
+    ``nir08`` rather than the generic ``nir``, which used to raise
+    ``KeyError: 'nir'`` when getting the band path.
+    """
+    prod = READER.open(
+        "https://planetarycomputer.microsoft.com/api/stac/v1/collections/landsat-c2-l2/items/LC09_L2SP_095022_20231119_02_T2",
+        remove_tmp=True,
+    )
+    assert prod is not None
+
+    band_paths = prod.get_band_paths([NIR])
+    # NIR is band 5 on Landsat-8/9: the resolved asset is the SR_B5 file
+    assert "B5" in str(band_paths[NIR])
+
+
 def test_s2_mpc():
     """Function testing the support of Sentinel-2 L2A (COG) constellation processed by MPC and linked via a STAC URL"""
     _test_core(

eoreader/products/optical/landsat_product.py

@@ -2048,18 +2048,36 @@ def _get_path(self, band_id: str) -> str:
                 if band is not None and f"B{band.id}" == band_id
             ][0]
             asset_name = EOREADER_STAC_MAP[band_name].value
+            if asset_name not in self.item.assets:
+                # Some collections name the asset differently from the STAC
+                # common name (e.g. Landsat Collection-2 exposes the NIR band
+                # as "nir08" instead of "nir"). Fall back to a fuzzy match
+                # against the actual asset keys (#307).
+                asset_name = self._get_closest_asset(asset_name)
         else:
-            try:
-                asset_name = difflib.get_close_matches(
-                    band_id, self.item.assets.keys(), cutoff=0.5, n=1
-                )[0]
-            except Exception as exc:
-                raise FileNotFoundError(
-                    f"Impossible to find an asset in {list(self.item.assets.keys())} close enough to '{band_id}'"
-                ) from exc
+            asset_name = self._get_closest_asset(band_id)
 
         return self.sign_url(self.item.assets[asset_name].href)
 
+    def _get_closest_asset(self, name: str) -> str:
+        """
+        Find the STAC asset whose name is closest to the given one.
+
+        Args:
+            name (str): Asset name to look for
+
+        Returns:
+            str: Closest asset name
+        """
+        try:
+            return difflib.get_close_matches(
+                name, self.item.assets.keys(), cutoff=0.5, n=1
+            )[0]
+        except Exception as exc:
+            raise FileNotFoundError(
+                f"Impossible to find an asset in {list(self.item.assets.keys())} close enough to '{name}'"
+            ) from exc
+
     def _read_mtd(self, force_pd=False) -> (etree._Element, dict):
         """
         Read Landsat metadata as: