Improve documentation for Xarray Python embedding

[DanielAdriaansen]

Describe the Enhancement

More specifics would be helpful on how to use Xarray with Python embedding in MET. Specifically:

1. Currently only DataArray objects are supported
2. The "attrs" associated with the DataArray must conform to MET standards. The documentation should more clearly define the expected types and templates for each supported attribute item, rather than simply a "sample" attributes dictionary.
3. Dataset objects can be used, but include an example of how to subset them and retain the necessary attrs MET requires

Time Estimate

4 hours

Relevant Deadlines

NONE

Funding Source

2790541

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• METplus, MET, METdatadb, METviewer, METexpress, METcalcpy, METplotpy

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[DanielAdriaansen]

Is there a way to check if the object is a DataArray prior to MET trying to access it? I.e., is there C++ code to identify an Xarray DataArray object? Or should this be for the user to enforce?

[DanielAdriaansen]

Segmentation fault returned if Dataset object passed. Likely because there are multiple variables in a Dataset and not just a single ndarray.

If a user has a Dataset (ds) object, they can subset it to a single DataArray (da) object and retain the attributes associated with the Dataset like this:
da = xr.DataArray(ds.varname,attrs=ds.attrs)

[DanielAdriaansen]

See here: #1470 (comment) for required attributes and their C++ formats for Python embedding.

[JohnHalleyGotway]

@DanielAdriaansen can you please take a look at this issue to see if the work is done? And if so, please close it.