Add an API to access as much original metadata as possible

Within xarray there is no easy way to expose the full XML metadata in the files inside the annotation folder.

Options:

• add an entries into .attrs that contain the return value of xmlschema.XMLSchema(schema_path).to_dict(annotation_path) [BUT, such objects cannot be saved as netCDF]
• add an xarray accessor with a metadata exploration API
• provide metadata exploration API functions in xarray_sentinel

Note that the I didn’t find any XSD for the manifest.safe, so we may need to keep to option to return an ElementTree representation of the XML.

[aurghs]

• add an entries into .attrs that contain the return value of xmlschema.XMLSchema(schema_path).to_dict(annotation_path)

if we store a dictionary in .attrs the data will be not serializable into a netCDF.

[alexamici]

Thinking more about the accessor-interface I’m now of the opinion that there’s no clean way to add the exploration API to the Dataset object because it is not the right place for it.

For what it is worth, my suggestion is to go with option 3 above:

provide metadata exploration API functions in xarray_sentinel