Versioned standardIDs for standard vocabularies? Also, including IVOA attributes in Avro schemas

[Dubois-Felsmann, Gregory P.]

Hi, Markus,

Thank you for the quick reply.

You acknowledged that UCDs don't seem to be RDF-izable, and presumably that applies to VOUnits as well, given the complex rules for composing unit strings from the defined atoms?  So for VOUnits as well, the only formal identifier to use would be the ivo://ivoa.net/std one?

You wrote:
> That way, it turns out *one* way to reference UCDs is
> ivo://ivoa.net/std/UCD (which is the UCD standard rather than the UCD
> list; I don't think the latter has a standards record yet, but I also
> think the base spec is the better target).

And later:

>UCDs, at this point, aren't a proper IVOA vocabulary, and will never
> exactly be, because they have a grammar that's (I think) impossible
> to map into RDF.  So, for them I'd suggest "This is a ucd" would
> always mean referencing ivo://ivoa.net/standards/ucd.

Are both of those URIs equally valid ("std/UCD" vs. "standards/ucd")?  Is there a distinction between them we should be aware of?

Apart from some Registry-specific restrictions that you helped explain about how the specific "#endpoint-version" fragment identifiers can be used, can you summarize why you think that a vocabulary identifier should not contain a version number?  Is this because there's an implicit (or perhaps explicit, that I haven't absorbed) policy that vocabulary terms will never be withdrawn?

Thanks,
Gregory

--
Gregory Dubois-Felsmann, Ph.D. | Senior Staff Scientist | Caltech/IPAC
Science Platform Scientist, Vera C. Rubin Observatory
Pipeline System Designer, NASA SPHEREx mission
Mail Code MR 100-22 | Pasadena, CA 91125-2200 | gpdf at ipac.caltech.edu

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