Fix reading netcdf generated from FA file (#401)

* Fix reading netcdf generated from FA file

src/earthkit/data/readers/netcdf/dataset.py

@@ -117,9 +117,18 @@ def _get_latlon(self, data_array, flatten=False, dtype=None):
         keys, coords = self._get_xy_coords(data_array)
 
         points = dict()
-        if "latitude" in self._ds and "longitude" in self._ds:
-            latitude = self._ds["latitude"]
-            longitude = self._ds["longitude"]
+
+        def _get_ll(keys):
+            for key in keys:
+                if key in self._ds:
+                    return self._ds[key]
+
+        lat_keys = ["latitude", "lat"]
+        lon_keys = ["longitude", "lon"]
+        latitude = _get_ll(lat_keys)
+        longitude = _get_ll(lon_keys)
+
+        if latitude is not None and longitude is not None:
             if latitude.dims == coords and longitude.dims == coords:
                 latitude = latitude.data
                 longitude = longitude.data

src/earthkit/data/readers/netcdf/fieldlist.py

@@ -27,9 +27,6 @@ def get_fields_from_ds(
     field_type=None,
     check_only=False,
 ):  # noqa C901
-    # Select only geographical variables
-    has_lat = False
-    has_lon = False
 
     fields = []
 
@@ -47,6 +44,10 @@ def _skip_attr(v, attr_name):
         _skip_attr(v, "grid_mapping")
 
     for name in ds.data_vars:
+        # Select only geographical variables
+        has_lat = False
+        has_lon = False
+
         if name in skip:
             continue
 

tests/netcdf/test_netcdf_geography.py

@@ -239,6 +239,14 @@ def test_netcdf_to_latlon_laea():
             assert np.isclose(v["lat"][x], ref[i]), f"{i=}, {x=}"
 
 
+def test_netcdf_forecast_reference_time():
+    ds = from_source("url", earthkit_remote_test_data_file("test-data", "fa_ta850.nc"))
+
+    assert len(ds) == 37
+    assert ds[0].metadata("valid_datetime") == "2020-01-23T00:00:00"
+    assert ds[5].metadata("valid_datetime") == "2020-01-23T05:00:00"
+
+
 if __name__ == "__main__":
     from earthkit.data.testing import main