Voc in the VO 2 / remarks

[Frederic V. Hessman]

> On 3 Jun 2020, at 09:27, Markus Demleitner <msdemlei at ari.uni-heidelberg.de> wrote:
> 
> Hi François,
> 
> Thanks for your feedback.
> 
> On Tue, Jun 02, 2020 at 07:32:46PM +0200, François Bonnarel wrote:
> 
>>       1 ) VEI instead of VEP : "Vocabulary Enhancment Issue", instead of
>> Vocabulary Enhancment Proposal   : The issue will be centered on a rationale
>> and not on a single term. Some discussions have shown that a term can be
>> preferred to another one with the same rationale and definition. A term can
>> also become the head term of a whole hierachy during the discussion
> 
> Frankly, that would rank rather high on my pain scale.  We don't do
> bug tracking with VEPs (perhaps there's a place for that, too, but
> I'm pretty sure that needs a different tool).  No, each VEP
> *proposes* a very specific action, and that's by design: discussions
> should be exactly to the point, being able to assess concrete
> consequences.
> 
>>       2 ) for the  same reason (incomplete discussion) "Preliminary" terms
>> should not be set in the "official" vocabulary list even with the
>> "preliminary" tag. Examples using those terms should be provided in
>> prototype services or realistic example files.
> 
> That would be a bit lower, but still high on my pain scale.  I've
> designed the "preliminary" mechanism in order to discourage the
> definition of terms just because we believe they might one day be
> useful.  Experience shows that such beliefs quite regularly turn out
> to be wrong, and cleaning up the resulting mess isn't fun.
> 
> Instead, I'd like to have a mechanism where something comes into
> being when it is required in a *live* service (or interpreted by a
> non-trivial client) -- that, in my view, is a necessary condition for
> something to be a good idea (of course, it's not a sufficient
> condition, which is why we're still discussing after a VEP).  
> 
> Plausible examples IMHO aren't enough -- if there's no immediate need
> for a term, we should wait until that immediate need comes up, at
> which point we probably better understand the problem we're trying to
> solve.

I don't agree.  François is thinking of Voc primarily as a system of ontologies - of data models - which of course need to be tightly constrained in order to be useful.  I agree with Markus that we need something simple and quickly useful.  For that reason, I think our goal has to be to support vocabularies as simple term lists with or without much ontological frill.  The usefulness of hierarchical (avoiding the term "ontogolical") information within a vocabulary depends on the use case.  A term list is most useful when the end-user easily finds the terms she needs.  If a useful term isn't present, the motivation to search for another vocabulary is modest (unless we provide simple tools that do this), the motivation to put up ones' own VO-compatible vocabulary as a fix is highly limited and the expectation that some external gremium will quickly add a term when asked is zero. This is why I wasn't so happy when UAT turned out to be highly stripped down from the original IAU terms list.  If terms are rarely used - no, my VO app doesn't need the term "armillarly sphere" - does your computer really care?

Rick