New issue?: vocabulary maintenance [vocabset-5]

[Norman Gray]

Rick and all,

On 2008 Feb 5, at 21:40, Frederic V. Hessman wrote:

>> Of these, I think the core ones are the A&A vocab, the IVOA-T and  
>> AOIM.
>>
>
> Whoa!  The "core" ones we've been talking about are A&A (no- 
> brainer), AOIM (good for internal IVOA politics),

No dispute there.

> UCD (an informal suggestion of how to standarize UCD keyword  
> publishing),

I've cast doubts before about the appropriateness of including a UCD  
vocabulary in this exercise, but I'd like to recant them.  The  
vocabularies other than UCD are describing things that astronomers  
study, whereas UCD is describing data types, which is a very different  
thing.  But even though it's unlikely there will be mappings from a  
SKOSified UCD to the other vocabularies, the UCDs are still a  
vocabulary, so no more quibbles from me on _those_ grounds (but see  
below).

> and IAU-93 (on historical principle).   The IVOA-T is definitely not  
> ready to be called "core" and we purposefully left it out of the list.

...which is why you titled the relevant section `Towards an IVOA  
Thesaurus' -- I see.

There's a bigger range of expectations here than I thought.  I had  
thought that the idea of what we have come to call the IVOA-T was that  
it would be essentially the IAU-93 thesaurus with some of the more  
egregious problems straightforwardly updated.  That is, it would be  
quite a small project to produce the first public version of the IVOA- 
T, viewed as an updated version of IAU-93.

Some here, however, clearly see it or have come to see it as involving  
much more (in some cases very much more) substantial updating and  
reworking.

Would it be reasonable to produce such a basic update in the couple of  
months we're aiming for?

The two options seem to be:

1. Publish just the IAU-93, but with a prominent notice saying we know  
it's out of date, and this is just an exercise (the disadvantage is  
that this starts to look redundant, or alternatively that the fact  
that `everyone knows it's out of date' might partly undermine the  
standard).

2. Publish the IAU-93 plus a minimally updated IVOA-T, with a note  
saying that this is not intended to be complete, but that it  
nonetheless has the prime virtue of existence, and can act as the  
basis for a fuller, separate, improvement effort.  This route has some  
precedent in the way that UCDs first appeared.

My vote would be for (2); Rick, you'd go for (1), yes?

>> Constellations: I get the impression this is simple and done, and  
>> whether or not it provides a persistent standard, it should be a  
>> good example.
>>
> This was strictly meant as a realistic example of very modest size.   
> Since it's officially a real vocabulary and the names are not in  
> IAU-93, we can simply keep it officially even though nobody would  
> really complain if we didn't (well, the AOIM guys should actually be  
> very pleased, but....).

OK.

>> AT, ATEL, GCN, CBAT, ...: these sound pretty easy, but the list is  
>> getting rather long now.
>>
> I suggest that the VOEvent crew do AT as homework and as an example  
> of the first vocabulary to be nominally created outside of the  
> semantics working group.

An excellent point of view.



Noting Rob's

> Keep the initial list short.  Our goal isn't to anticipate all  
> future participants, rather to provide a mechanism that will permit  
> new (or quite mature) vocabularies to be added when needed.

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.

I suggest omitting the SKOSified UCDs on the grounds that their  
subject is conceptually separate, and in any case they might be more  
rationally published via the UCD maintenance process.

I agree with Rick about leaving the various event vocabularies as  
VOEvent homework.

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....

So just three vocabularies?  Any objections? This is issue  
[vocabset-5], by the way.



Rob, again:

> Is there a practical limit to the number of vocabularies we will be  
> able to support?  There may ultimately be dozens or hundreds (or  
> more) distinct dialects.

The practical limits will I think be twofold: can UIs cope with this  
range in any helpful fashion?; and can the community collectively  
manage to curate this many vocabularies and their mappings without  
them all going stale?  I don't believe there are important technical  
limits.  I can imagine a dozen vocabularies, some of them rather small.

> This raises, yet again, the point of finding a permanent place  
> within www.ivoa.net to put these things.....

I'm glad you raised that. I don't think there's a deep problem here,  
but I'm not sure where it should be discussed.  I imagine I just mail  
Bruno (the document coordinator).

>> Presuming that we'll be wanting to add mappings between these  
>> vocabularies (that being half the point of this project), this is  
>> starting to look like a lot of work. Perhaps A&A, IVOAT and AOIM  
>> would be an adequately large set to include in the standard after  
>> all.
>>
> No, I'd say we should include mappings between A&A and AIOM simply  
> to show that it can be done.   Leave the rest for the question of  
> what vocabulary is going to be the best lingua franca.

Let's see how Alasdair (G) gets on with his mappings editor.  It might  
turn out to be easy to add lots.  At any rate, I agree we need at  
least some mappings in the standard.

All the best,

Norman


-- 
Norman Gray  :  http://nxg.me.uk
eurovotech.org  :  University of Leicester