New issue?: vocabulary maintenance [vocabset-5]

[Frederic V. Hessman]

>> There's a very simple reason why there needs to be a SKOS-ified  
>> version of UCD:  we desperately need to be able to link vocabulary  
>> words to UCD tokens.  If we can't do this, then we'll need to  
>> replace all that UCD is and put an equivalent in a different  
>> vocabulary (e.g. IVOAT), which sounds like a pretty stupid thing to  
>> do.
>
> Is there a use-case that should go in the document?  It appears to  
> me that UCDs already have a place -- and a special attribute in the  
> VOTable spec, no less -- so that it's not clear to me what  
> SKOSifying them would add.  I'm not denying that this scenario  
> exists, but it's one which I at least haven't thought of (and  
> probably should have), and which I'm not picking up from your  
> description here.

Of course UCDs (at least currently) have a life of their own, and  
that's not going to change any time soon.   Exactly BECAUSE IAU-93,  
UCD and AOIM the only currently used official "vocabularies" we can't  
simply pretend that the issue of current format versus future format  
is not important.  In the case of AOIM, we have an easy time because  
there is not real computer-readable normative document, and the AOIM  
people should be delighted that we've found a handy format for them to  
publish with.    With UCD, there is a normative document of sorts and  
SKOS alone cannot express the additional info embodied in the "syntax  
codes", making it impossible to suggest a quick format change  
(although this problem could, of course, be solved).  This said, there  
is still a very good reason to produce a version of UCD in SKOS  
exactly so we can pretend it's a normal vocabulary.   This should not  
be described as a bug, but a feature.   Every time the UCD list is  
updated, we insure that the SKOS version is too, and everybody is happy.

>>> The present IVOA-T IS a minimally updated IAU-93, but "minimally  
>>> updated" doesn't simply mean we've added a few missing words.   
>>> There is some concern that a discussion of the merits of  
>>> publishing an IVOA-T will distract from the expected easy  
>>> acceptance of the basic vocabulary proposal.   On the other hand,  
>>> if we tell our colleagues "be fruitful and let vocabularies  
>>> multiply in the VO" but then say that the only ones available at  
>>> first, A&A, AOIM, and IAU-93, aren't really enough to cover the  
>>> basics, then they'll rightly say "why bother" or simply use IAU-93  
>>> after all (like Rob).
>>> I suggest that we include in the Vocabulary standard document the  
>>> three vocabularies A&A, AOIM, and either IAU-93 or IAU-93/IVOA-T,  
>>> depending on how we resolve this.
>>>
>> This is a good point:  the vocabularies we discuss at more length  
>> in the standards document don't have to be the same ones which the  
>> IVOA publishes.  Still, if we can produce several useful  
>> vocabularies (each having it's own particular use) and we're not  
>> stepping on anybodies semantic toes, why can't we simply produce a  
>> nice batch of vocabularies to start out with?
>
> Are you, then, moving towards the position that the IVOA-T shouldn't  
> be included in this vocabularies standard, but should be the subject  
> of a parallel standardisation effort?

This is what we decided ages ago, in fact during the process of moving  
from Andrea, myself, et al.'s original still-born VOcabulary proposal  
to the present SKOS proposal.

I'd be happy with a plan to clean up the rest of IVOA-T and submit it  
quickly as an updated version of IAU-93, with many of the problems of  
the old thesaurus, but with many things also cleaned up and  
improved.   I haven't gotten the feeling from all that this is  
perceived as something we should do......

Before, a broad committee went through the IAU thesaurus, something  
I'd rather not have to go through again.   Since the basis is IAU-93,  
the IAU shouldn't complain if the IVOA produces an update for it's own  
purposes.   The question is, whether the other IVOA groups will  
complain that they didn't have a change to put in major input.   I  
think this could be a simple procedure if we can then tell our  
complaining IVOA collegues - "Hey - not our fault, we're just  
following the IAU!" and offer to accept last-minute modifications/ 
additions.

Do I see any hands on offers to work on a WD for IVOA-T?

> I'm not opposed to that in principle, but it slightly worries me,  
> since I think that publication of an updated IAU-93 (=IVOA-T) would  
> be important for the vocabularies effort, and it would be  
> unfortunate if they were published too far apart from each other.

I agree - we're going to make it more difficult for people to jump- 
start their use of vocabularies if all they have is IAU-93.

>>> I don't know what to do with the constellation vocabulary.  On the  
>>> one hand, it's simple; on the other, 4 is 33% more than 3....
>>
>> Exactly what we now have:  it is a usable if limited vocabulary  
>> derived for didactic purposes, being MUCH simpler than all the rest  
>> we're taking about.
>
> Fair enough.  No objections from me.  Does anyone else feel strongly  
> about Rick's constellation vocabulary being in the document?

Don't get me wrong - I have no strong feelings about the constellation  
vocabulary, it's just that it's a good place for people to start and  
nominally covers a semantic  need: the official source of  
constellation names in computer-readable format.  There are lots of  
things like this which could result in small, limited vocabularies,  
e.g. the list of astronomically observable molecules, ....      We  
should rename it, however: http://www.ivoa.net/{pathname-for- 
vocabularies}/constellations   ("Sky" is a bit too presumptuous).

Rick