_RegridTargetPrep(): Handle existing lon/lat dims/variables.

src/landusedata/utils.py

@@ -21,6 +21,16 @@ def _RegridTargetPrep(regrid_target):
     by xesmf.  As such, this function renames the dimensions.  It also adds
     lat/lon coordinates based on the LONGXY and LATIXY variables.
     """
+
+    # Skip if lat and lon are already the dimension names
+    if "lat" in regrid_target.dims and "lon" in regrid_target.dims:
+        return regrid_target
+
+    # Drop dimension variables if they already exist
+    regrid_target = regrid_target.drop_vars("lat", errors="ignore")
+    regrid_target = regrid_target.drop_vars("lon", errors="ignore")
+
+    # Rename dimensions and add coordinates
     regrid_target = regrid_target.rename_dims(dims_dict={'lsmlat':'lat','lsmlon':'lon'})
     regrid_target['lon'] = regrid_target.LONGXY.isel(lat=0)
     regrid_target['lat'] = regrid_target.LATIXY.isel(lon=0)