New callbacks to standardise some dim names

src/CSET/operators/_utils.py

@@ -51,7 +51,7 @@ def get_cube_yxcoordname(cube: iris.cube.Cube) -> tuple[str, str]:
     Y_COORD_NAMES = ["latitude", "grid_latitude", "projection_y_coordinate", "y"]
 
     # Get a list of coordinate names for the cube
-    coord_names = [coord.name() for coord in cube.coords()]
+    coord_names = [coord.name() for coord in cube.dim_coords]
 
     # Check which x-coordinate we have, if any
     x_coords = [coord for coord in coord_names if coord in X_COORD_NAMES]

src/CSET/operators/read.py

@@ -198,6 +198,8 @@ def callback(cube: iris.cube.Cube, field, filename: str):
         _lfric_normalise_callback(cube, field, filename)
         _lfric_time_coord_fix_callback(cube, field, filename)
         _longitude_fix_callback(cube, field, filename)
+        _fix_spatialcoord_name_callback(cube)
+        _fix_pressurecoord_name_callback(cube)
 
     return callback
 
@@ -333,6 +335,44 @@ def _longitude_fix_callback(cube: iris.cube.Cube, field, filename):
     return cube
 
 
+def _fix_spatialcoord_name_callback(cube: iris.cube.Cube):
+    """Check latitude and longitude coordinates name.
+
+    This is necessary as some models define their grid as 'grid_latitude' and 'grid_longitude'
+    and this means that recipes will fail - particularly if the user is comparing multiple models
+    where the spatial coordinate names differ.
+    """
+    import CSET.operators._utils as utils
+
+    try:
+        y_name, x_name = utils.get_cube_yxcoordname(cube)
+    except ValueError:
+        # Don't modify non-spatial cubes.
+        return cube
+
+    # We only want to modify instances where the coordinate system is actually
+    # latitude/longitude, and not touch the cube if the coordinate system is say
+    # meters.
+    if y_name in ["latitude"] and cube.coord(y_name).units == "degrees":
+        cube.coord(y_name).rename("grid_latitude")
+    if x_name in ["longitude"] and cube.coord(x_name).units == "degrees":
+        cube.coord(x_name).rename("grid_longitude")
+
+    return cube
+
+
+def _fix_pressurecoord_name_callback(cube: iris.cube.Cube):
+    """Rename pressure_level coordinate to pressure if it exists."""
+    # We only want to modify instances where the coordinate system is actually
+    # latitude/longitude, and not touch the cube if the coordinate system is say
+    # meters.
+    for coord in cube.dim_coords:
+        if coord.name() == "pressure_level":
+            coord.rename("pressure")
+
+    return cube
+
+
 def _check_input_files(input_path: Path | str, filename_pattern: str) -> Iterable[Path]:
     """Get an iterable of files to load, and check that they all exist.
 

tests/operators/test_read.py

@@ -240,3 +240,36 @@ def test_lfric_time_coord_fix_callback_no_time():
     cube = iris.cube.Cube([0, 0, 0], aux_coords_and_dims=[(length_coord, 0)])
     read._lfric_time_coord_fix_callback(cube, None, None)
     assert len(cube.coords("time")) == 0
+
+
+def test_pressurecoordfix_callback():
+    """Check that pressure_level is renamed to pressure if it exists."""
+    cube = iris.load_cube("tests/test_data/transect_test_umpl.nc")
+    cube.coord("pressure").rename("pressure_level")
+    read._fix_pressurecoord_name_callback(cube)
+    assert (
+        str(cube.coords)
+        == "<bound method Cube.coords of <iris 'Cube' of air_temperature / (K) (time: 2; pressure: 16; latitude: 6; longitude: 6)>>"
+    )
+
+
+def test_spatialcoordrename_callback():
+    """Check that spatial coord gets renamed if it is not grid_latitude."""
+    # This cube contains 'latitude' and 'longitude'
+    cube = iris.load_cube("tests/test_data/transect_test_umpl.nc")
+    read._fix_spatialcoord_name_callback(cube)
+    assert (
+        str(cube.coords)
+        == "<bound method Cube.coords of <iris 'Cube' of air_temperature / (K) (time: 2; pressure: 16; grid_latitude: 6; grid_longitude: 6)>>"
+    )
+
+
+def test_spatialcoordnotexist_callback():
+    """Check that spatial coord returns cube if cube does not contain spatial coordinates."""
+    cube = iris.load_cube("tests/test_data/transect_test_umpl.nc")
+    cube = cube[:, :, 0, 0]  # Remove spatial dimcoords
+    read._fix_spatialcoord_name_callback(cube)
+    assert (
+        str(cube.coords)
+        == "<bound method Cube.coords of <iris 'Cube' of air_temperature / (K) (time: 2; pressure: 16)>>"
+    )

tests/operators/test_utils.py

@@ -21,23 +21,23 @@
 
 def test_missing_coord_get_cube_yxcoordname_x(regrid_rectilinear_cube):
     """Missing X coordinate raises error."""
-    regrid_rectilinear_cube.remove_coord("longitude")
+    regrid_rectilinear_cube.remove_coord("grid_longitude")
     with pytest.raises(ValueError):
         operator_utils.get_cube_yxcoordname(regrid_rectilinear_cube)
 
 
 def test_missing_coord_get_cube_yxcoordname_y(regrid_rectilinear_cube):
     """Missing Y coordinate raises error."""
-    regrid_rectilinear_cube.remove_coord("longitude")
+    regrid_rectilinear_cube.remove_coord("grid_longitude")
     with pytest.raises(ValueError):
         operator_utils.get_cube_yxcoordname(regrid_rectilinear_cube)
 
 
 def test_get_cube_yxcoordname(regrid_rectilinear_cube):
     """Check that function returns tuple containing horizontal dimension names."""
     assert (operator_utils.get_cube_yxcoordname(regrid_rectilinear_cube)) == (
-        "latitude",
-        "longitude",
+        "grid_latitude",
+        "grid_longitude",
     )