Dropping bound coordinate values

cmip6_preprocessing/preprocessing.py

@@ -8,6 +8,9 @@
 from cmip6_preprocessing.utils import _maybe_make_list
 
 
+_drop_coords = ["bnds", "vertex"]
+
+
 def cmip6_renaming_dict():
     """a universal renaming dict. Keys correspond to source id (model name)
     and valuse are a dict of target name (key) and a list of variables that
@@ -441,7 +444,6 @@ def fix_metadata(ds):
 
 
 def combined_preprocessing(ds):
-    ds = ds.copy()
     # fix naming
     ds = rename_cmip6(ds)
     # promote empty dims to actual coordinates
@@ -462,4 +464,5 @@ def combined_preprocessing(ds):
     ds = maybe_convert_bounds_to_vertex(ds)
     ds = maybe_convert_vertex_to_bounds(ds)
     ds = fix_metadata(ds)
+    ds = ds.drop_vars(_drop_coords, errors="ignore")
     return ds

tests/test_preprocessing.py

@@ -450,6 +450,26 @@ def test_fix_metadata():
 ### Combination test - involving###
 
 
+@pytest.mark.parametrize("add_coords", [True, False])
+@pytest.mark.parametrize("shift", [0, 10])
+def test_combined_preprocessing_dropped_coords(add_coords, shift):
+    """Check if coordinates are properly dropped"""
+    # create a 2d dataset
+    xlen, ylen, zlen = (10, 5, 1)
+    ds = (
+        create_test_ds("x", "y", "dummy", xlen, ylen, zlen).squeeze().drop_vars("dummy")
+    )
+    x_bnds = xr.concat([ds.x, ds.x], "bnds")
+    ds = ds.assign_coords(x_bounds=x_bnds)
+
+    if add_coords:
+        ds = ds.assign_coords(bnds=np.arange(len(ds.bnds)) + shift)
+
+    ds = combined_preprocessing(ds)
+
+    assert "bnds" not in ds.coords
+
+
 def test_combined_preprocessing_mislabeled_coords():
     """Test if the renaming is applied to datavariables and then if they are moved to the coords."""
     # create a 2d dataset

tests/test_preprocessing_cloud.py

@@ -8,7 +8,7 @@
 import xarray as xr
 
 from cmip6_preprocessing.grids import combine_staggered_grid
-from cmip6_preprocessing.preprocessing import combined_preprocessing
+from cmip6_preprocessing.preprocessing import _drop_coords, combined_preprocessing
 from cmip6_preprocessing.utils import google_cmip_col, model_id_match
 
 
@@ -221,6 +221,9 @@ def test_check_dim_coord_values_wo_intake(
     # make sure lon and lat are 2d
     assert len(ds.lon.shape) == 2
     assert len(ds.lat.shape) == 2
+    for co in _drop_coords:
+        if co in ds.dims:
+            assert co not in ds.coords
 
 
 # this fixture has to be redifined every time to account for different fail cases for each test
@@ -288,6 +291,9 @@ def test_check_dim_coord_values(
     # make sure lon and lat are 2d
     assert len(ds.lon.shape) == 2
     assert len(ds.lat.shape) == 2
+    for co in _drop_coords:
+        if co in ds.dims:
+            assert co not in ds.coords
 
 
 ############################### Specific Bound Coords Test ###############################