Vocabulary terms in MANGO

[Markus Demleitner]

Dear Laurent,

On Wed, Nov 06, 2024 at 01:57:44PM +0100, Laurent Michel via semantics wrote:
> I wrote a few comments below, but to be short I propose
> to take the following actions:
>
> - create a vocabulary named "property_qualifier"

Uh... Let me be very frank and say that I don't like that name much
exactly because it is so generic; the name would probably fit for
every vocabulary we already have.  I think we can do a lot better if
we spell out:

(a) properties of what?
(b) how, i.e., in which way, are these properties qualified?

I'm pretty sure we will find a much more descriptive and much less
generic name if you sketch the concepts you'd like to include.  Or
for that matter, name*s*, if that's what it takes.

> - serialize it as "property_qualifier.desise"
>     - is desise a suitable format?

No, don't bother with anything so formal.  The actual input will be a
simple CSV anyway, see
https://github.com/ivoa-std/Vocabularies/blob/master/examples/terms.csv
for an, pun intended, example.  But really, just the identifiers,
descriptions and possibly the hierarchy of the concepts will be
enough, and I'll be happy to cover the technical side.

> - put this file in a 'vocabulary' folder into the MANGO projects
>   to make it part of the RFC

I'd actually much prefer if we work in
https://github.com/ivoa-std/Vocabularies immediately.  That way, the
vocabulary's history will be where it belongs, and PRs within that
repo will later let people figure out what happened to it when they
want to understand why something is the way it is.

> - change the model accordingly
> - open a PR with that stuff

There ought to be a PR against Mango describing the use of the
vocabulary and stating its URI, but that's about it.

I'm sure you are aware that VO-DML actually has a hook for this kind
of thing?  See sect. 4.15, where we probably want to steer clear of
SKOS these days unless we actually need to looser properties
(explanation for that preference on request).  Perhaps we can even
prototype more formal rules for bridging VO-DML and VocInVO2?  Just
to explain the lack of existing rules: VO-DML predates or current,
more formal, vocabularies.

> OK, let's start we something simple.
> e.g.
>                    |- raw-data
> calibration-level -|- ...
>                    |- calibrated-data

That would be a vocabulary of its own, right?  In this particular
case, it would be great if the descriptions (or something else)
discussed your concepts' relationships to what EPN-TAP has in its
description of the processing_level column (EPN-TAP2, CODMAC, PSA,
PDS3, PDF4, and Obscore levels).

> Looking at https://www.ivoa.net/rdf/, I see no obvious place for
> the terms I'm proposing.  The MANGO scope is to enhance the
> desciption of complex quantities exploded in table columns.  AFAIK,
> there is no vocabulary covering this field yet.

Ummm: Did you mean to write "exploded" here?  If so, what does that
mean here?

If this is what I think it is, I strongly suspect you want multiple
vocabularies; for instance calibration-level, photometry-type, etc.
Quite possibly, you then want to forsee full concept URIs
("http://www.ivoa.net/rdf/calibration-level#raw" rather than just
"raw" or "#raw") whereever you keep the concept identifiers.

Having several distinct vocabularies that MANGO will use is no reason
for alarm.  Many small, focused vocabularies are generally preferable
to some behemoth that makes you forget what exactly it's for.

Thanks,

              Markus