Raise exception if regrid2 is called with multidimensional coordinates

Author: jasonb5

tests/test_regrid.py

@@ -485,6 +485,71 @@ def setup(self):
             }
         )
 
+    def test_multidim(self):
+        # 11,20     11,21
+        # 1,0       1,1
+        #
+        #
+        # 0,0       0,1
+        # 10,20     10,21
+        lat = np.array([[10, 10], [11, 11]])
+        lon = np.array([[20, 21], [20, 21]])
+        lat_bnds = np.array(
+            [
+                [[9.5, 9.5, 10.5, 10.5], [9.5, 9.5, 10.5, 10.5]],
+                [[10.5, 10.5, 11.5, 11.5], [10.5, 10.5, 11.5, 11.5]],
+            ]
+        )
+        lon_bnds = np.array(
+            [
+                [
+                    [19.5, 21.5, 21.5, 19.5],
+                    [20.5, 21.5, 21.5, 19.5],
+                ],
+                [
+                    [19.5, 21.5, 21.5, 19.5],
+                    [20.5, 21.5, 21.5, 19.5],
+                ],
+            ]
+        )
+
+        ds = xr.Dataset(
+            data_vars={
+                "ts": (("x", "y"), [[1.2, 1.3], [0.9, 2.2]]),
+                "lat_bnds": (("x", "y", "n"), lat_bnds),
+                "lon_bnds": (("x", "y", "n"), lon_bnds),
+            },
+            coords={
+                "lat": (
+                    ("x", "y"),
+                    lat,
+                    {
+                        "units": "degrees_north",
+                        "long_name": "latitude",
+                        "axis": "y",
+                        "bounds": "lat_bnds",
+                    },
+                ),
+                "lon": (
+                    ("x", "y"),
+                    lon,
+                    {
+                        "units": "degrees_east",
+                        "long_name": "longitude",
+                        "axis": "x",
+                        "bounds": "lon_bnds",
+                    },
+                ),
+            },
+        )
+
+        output_grid = grid.create_gaussian_grid(4)
+
+        regridder = regrid2.Regrid2Regridder(ds, output_grid)
+
+        with pytest.raises(RuntimeError):
+            regridder.horizontal("ts", ds)
+
     # source ordering is time, height, lat, lon
     @pytest.mark.parametrize(
         "ordering",

xcdat/regridder/regrid2.py

@@ -5,7 +5,7 @@
 import xarray as xr
 
 import xcdat as xc
-from xcdat.axis import get_dim_keys
+from xcdat.axis import get_dim_coords, get_dim_keys
 from xcdat.regridder.base import BaseRegridder, _preserve_bounds
 from xcdat.regridder.grid import create_mask, create_nan_mask
 
@@ -709,10 +709,25 @@ def _get_bounds_ensure_dtype(ds, axis):
     except KeyError:
         pass
 
+    # try to determine actual cause
+    # can be hidden by call stack get_bounds -> _validate_axis_arg -> get_dim_coords
+    # get_dim_coords by default does not retrieve multidimensional coords
     if bounds is None:
-        raise RuntimeError(f"Could not determine {axis!r} bounds")
+        if _is_multidim_axis(ds, axis):
+            raise RuntimeError("Regrid2 does not support multidimensional coordinates")
+        else:
+            raise RuntimeError(f"Could not determine {axis!r} bounds")
 
     if bounds.dtype != np.float32:
         bounds = bounds.astype(np.float32)
 
+    if len(bounds.shape) > 2:
+        raise RuntimeError("Rregrid2 doesn't support multidimensional coordinates")
+
     return bounds.values
+
+
+def _is_multidim_axis(ds, axis):
+    coord = get_dim_coords(ds, axis, True)
+
+    return len(coord.shape) > 1