Merge pull request #112 from zmoon/remap

Fix `.monet.remap_xesmf()` for Dataset-to-Dataset

.gitignore

@@ -4,6 +4,7 @@
 *~
 .DS_Store
 docs/_build/
+monet_xesmf_regrid_file.nc
 
 
 # Default GitHub .gitignore for Python below:

environment-dev.yml

@@ -0,0 +1,25 @@
+name: monet-dev
+channels:
+  - conda-forge
+  - nodefaults
+dependencies:
+  - python=3.9
+  #
+  # core
+  - cartopy
+  - dask
+  - matplotlib
+  - netcdf4
+  - pydecorate
+  - pandas
+  - seaborn
+  - xarray
+  #
+  # optional
+  - pyresample
+  - xesmf # non-Windows only!
+  #
+  # test/dev
+  - ipykernel
+  - ipython
+  - pytest

monet/monet_accessor.py

@@ -1477,13 +1477,14 @@ def remap_xesmf(self, data, **kwargs):
                     raise TypeError
             except TypeError:
                 print("data must be an xarray.DataArray or xarray.Dataset")
+                # TODO: raise
 
     def _remap_xesmf_dataset(self, dset, filename="monet_xesmf_regrid_file.nc", **kwargs):
-        skip_keys = ["latitude", "longitude", "time", "TFLAG"]
-        vars = pd.Series(dset.variables)
+        skip_keys = ["lat", "lon", "time", "TFLAG"]
+        vars = pd.Series(list(dset.variables))
         loop_vars = vars.loc[~vars.isin(skip_keys)]
         dataarray = dset[loop_vars[0]]
-        da = self._remap_xesmf_dataarray(dataarray, self._obj, filename=filename, **kwargs)
+        da = self._remap_xesmf_dataarray(dataarray, filename=filename, **kwargs)
         self._obj[da.name] = da
         das = {}
         das[da.name] = da

monet/util/resample.py

@@ -126,4 +126,7 @@ def resample_xesmf(source_da, target_da, cleanup=False, **kwargs):
             ds.attrs = source_da.attrs
             return ds
         else:
-            return regridder(source_da)
+            da = regridder(source_da)
+            if da.name is None:
+                da.name = source_da.name
+            return da

pyproject.toml

@@ -9,3 +9,11 @@ line-length = 100
 known_first_party = "monet"
 profile = "black"
 line_length = 100
+
+[tool.pytest.ini_options]
+filterwarnings = [
+    "ignore:distutils Version classes:DeprecationWarning::",
+    """ignore:elementwise comparison failed; returning scalar instead:\
+       FutureWarning:xarray.core.dataarray:""",
+    # ^ looks to be coming from xESMF
+]

tests/test_remap.py

@@ -0,0 +1,48 @@
+import numpy as np
+import pytest
+import xarray as xr
+
+import monet  # noqa: F401
+
+
+def test_remap_ds_ds():
+    # Barry noted a problem with this
+
+    lonmin, latmin, lonmax, latmax = [0, 0, 10, 10]
+
+    def make_ds(*, nx=10, ny=10):
+        data = np.arange(nx * ny).reshape((ny, nx))
+        assert data.flags["C_CONTIGUOUS"], "xESMF wants this"
+
+        return xr.Dataset(
+            data_vars={"data": (("y", "x"), data)},
+            coords={
+                "latitude": ("y", np.linspace(latmin, latmax, ny)),
+                "longitude": ("x", np.linspace(lonmin, lonmax, nx)),
+            },
+        )
+
+    target = make_ds()
+    source = make_ds(nx=5)
+    # When we call `target.monet.remap_xesmf()`,
+    # data on the source grid is regridded to the target grid
+    # and added as a new variable.
+
+    # Check for cf accessor
+    assert hasattr(target, "cf")
+    with pytest.raises(KeyError, match="No results found for 'latitude'."):
+        target.cf.get_bounds("latitude")
+    assert hasattr(target.monet._obj, "cf")
+
+    # On the data DataArray directly
+    target.monet.remap_xesmf(source["data"])
+    ds1 = target.copy(deep=True)
+
+    # On the Dataset
+    # Note conservative methods don't work here because need cell bounds
+    target = target.drop_vars("data_y")
+    target.monet.remap_xesmf(source, method="nearest_d2s")
+    ds2 = target.copy(deep=True)
+
+    assert np.all(ds1.data == ds2.data), "original data should be same"
+    assert not np.all(ds1.data_y == ds2.data_y), "remapped data should be different"