update docs, add coord alias reset function

Author: chrishavlin

docs/examples/example_002_coord_aliases.ipynb

@@ -26,7 +26,9 @@ yt datasets have a fixed expectation for coordinate names. In cartesian, these
 coordinate names are ``'x'``, ``'y'``, ``'z'`` while for geographic coordinate systems
 the coordinate names are ``'latitude'``, ``'longtiude'`` and then either ``'altitude'``
 or ``'depth'``. To work with xarray variables defined with coordinate names that
-differ from these, yt_xarray provides some coordinate aliasing.
+differ from these, yt_xarray provides some coordinate aliasing, which in part relies
+on `cf_xarray <https://cf-xarray.readthedocs.io>`_ (if it is installed) for
+additional conversion to standard names.
 
 See :doc:`examples/example_002_coord_aliases` for an example.
 

docs/faq.rst

@@ -8,5 +8,5 @@
 # import the xarray accessor so it is registered with xarray
 
 from .accessor import YtAccessor
-from .accessor._xr_to_yt import known_coord_aliases
+from .accessor._xr_to_yt import known_coord_aliases, reset_coordinate_aliases
 from .yt_xarray import open_dataset

yt_xarray/__init__.py

@@ -324,10 +324,26 @@ def interp_validation(self, geometry):
 }
 
 
-known_coord_aliases = {}
+_default_known_coord_aliases = {}
 for ky, vals in _coord_aliases.items():
     for val in vals:
-        known_coord_aliases[val] = ky
+        _default_known_coord_aliases[val] = ky
+
+known_coord_aliases = _default_known_coord_aliases.copy()
+
+
+def reset_coordinate_aliases():
+    kys_to_pop = [
+        ky
+        for ky in known_coord_aliases.keys()
+        if ky not in _default_known_coord_aliases
+    ]
+    for ky in kys_to_pop:
+        known_coord_aliases.pop(ky)
+
+    for ky, val in _default_known_coord_aliases.items():
+        known_coord_aliases[ky] = val
+
 
 _expected_yt_axes = {
     "cartesian": set(["x", "y", "z"]),

yt_xarray/accessor/_xr_to_yt.py

@@ -566,3 +566,9 @@ def _bad_import(name, globals=None, locals=None, fromlist=(), level=0):
         with pytest.raises(ValueError, match=f"{clist[0]} is not"):
 
             _ = xr2yt._convert_to_yt_internal_coords(clist, xr_da)
+
+
+def test_coord_alias_reset():
+    xr2yt.known_coord_aliases["blah"] = "lwkerj"
+    xr2yt.reset_coordinate_aliases()
+    assert "blah" not in xr2yt.known_coord_aliases