generalize dims as X/Y when lat/lon or rlat/rlon

[vindelico]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• (If applicable) Documentation has been added / updated (for bug fixes / features).
• (If applicable) Tests have been added.
• This PR does not seem to break the templates.
• HISTORY.rst has been updated (with summary of main changes).
• Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• spatial dimensions can be generalized as X/Y when rechunking and will be mapped to rlon/rlat or lon/lat accordingly.
• The yml file can contain

rechunk:
time: -1
X: 100
Y: 100

instead of

rechunk:
time: -1
rlat: 100
rlon: 100

or

rechunk:
time: -1
lat: 100
lon: 100

This allows to handle grids on different projections together. Example: RDRSv2 (rlat/rlon) and ERA5-Land (lat/lon); different CORDEX-NA RCMs;

Does this PR introduce a breaking change?

No.

Other information:

The duplicated code preparing for rechunking from save_to_netcdf() and save_to_zarr() was refactored into a private function _rechunk_for_saving()

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[aulemahal]

Nice addition! Thanks!

[juliettelavoie]

Nice! Are you able to add a test ? You could create a test/test_io.py file with the same structure as the other test files with a test_rechunk_for_saving function.

[RondeauG]

Looks good! I would add a mention of this both in the Docstrings for save_to_zarr and save_to_netcdf (probably where rechunk is defined), as well as in the documentation: https://xscen.readthedocs.io/en/latest/notebooks/2_getting_started.html#Saving-files-to-disk

[vindelico]

Looks good! I would add a mention of this both in the Docstrings for save_to_zarr and save_to_netcdf (probably where rechunk is defined), as well as in the documentation: https://xscen.readthedocs.io/en/latest/notebooks/2_getting_started.html#Saving-files-to-disk

I changed the docstrings and and added a line about this in the notebook.

[vindelico]

Nice! Are you able to add a test ? You could create a test/test_io.py file with the same structure as the other test files with a test_rechunk_for_saving function.

test/test_io.py created.
I opted for four tests, to check if lat/lon, rlat/rlon are rechunked and when either is rechunked with X/Y as dims.

[RondeauG]

I can help with the tests, if you want.