# Vocabularies in the VO 2.0, first working draft

Mark Taylor M.B.Taylor at bristol.ac.uk
Fri Sep 20 01:35:29 CEST 2019

Markus,

On Fri, 6 Sep 2019, Markus Demleitner wrote:

> The first working draft of the new Vocabularies in the VO 2.0 has
> just hit the document repository at
> http://ivoa.net/documents/Vocabularies/ (I suspect that URI might yet
> change, but you'll get to the document from the index page in any
> case).

I've taken a look at this draft, though not at the tools or the
example vocabularies.

General comments, with reference to some of the points you raised

- On the whole it looks like a comprehensible and well-drafted
document that does reasonable things.

- Being able to mark terms as preliminary is a neat idea, I think
it will solve some practical problems.

- I am in favour of the non-RDF-tooling requirement; at least
I don't want to have to pull in a big RDF library to parse
these things.  The XML rules you give look fine, though I
haven't given much thought to whether other possibilities
(turtle or whatever) would work any better.

- I don't know/haven't thought enough to have an opinion on
whether this is the right level of complexity.  It doesn't
suggestions (ad-hoc XML/JSON, wider-only) it would no doubt
look better (i.e. shorter).  My feeling is that lack of
interoperability with non-VO technology is not going to be
much of a problem, but I could be wrong and then we might
regret not doing it.

- I wonder if the (somewhat detailed? somewhat heavy?) VEP
process should be documented elsewhere.
It seems like the kind of thing that we might decide
wants revision following experience of use, and unlike
the syntax/semantics content of the rest of the document,
it doesn't hurt anything if it changes at short notice,
so it would be annoying to have to push through a new
document revision just to change the processes.
So maybe: replace section 4.2 with a comment to the effect
that vocabulary updates will be managed by the Semantics WG
in consultation with the TCG, and break out the details
to a Note?  Or even a wiki page until we feel like it's
working smoothly?

I fixed a few typos (r5650).  I also have queries/suggestions on
a few more minor points:

- sec 1.3: "behind the hash character" - I'm not sure which
direction I expect 'behind' to mean in this context;
"after" would be less ambiguous?

- sec 2.2.11: "use case!\ref{uc:offline}" - I *think* that
exclamation mark is a typo, but I didn't like to delete it
in case it's some weird TeX magic.

- sec 3.1.1 and 3.2.1: skos:prefLabel is constrained to have
exactly one occurrence per concept but the text for
skos:definition seems to permit multiple occurrences.
Same applies to rdfs:label and rdfs:comment.
Is this intentional?  Having multiple definition/comment entries
sounds to me like it would be confusing and should be outlawed,
but maybe I'm missing something.

- sec 3.1.1: "Definitions that contain the preferred label
itself are at least suspicious" - well I think I see what you're
getting at but at least in the case that the label is a single
english word such an occurrence is going to be reasonable.
I'd be inclined to lay off the veiled threats, but it's not a
strong opinion.

- sec 3.1.2: appears to be missing the mandatory skos:definition element.

- Appendix A: I'm tempted to say that you should be more specific
about the file formats (CSV variant details, e.g. how to escape
commas; what's INI format).  But on reflection as long as there
are examples in place (I haven't so far looked at them) then it
probably is sufficient detail for this non-normative, and possibly
subject to change, text.

Mark

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/