[TAP] Summary: data type for column metadata

[Mark Taylor]

>From a TAP outsider (i.e. feel free to ignore in favour of people
with a better idea of what they're talking about):

On Thu, 16 Apr 2009, Gerard wrote:

>
> > 2. add single additional optional metadata coordinate system 
> > spec, with values coming from tables in STC, FITS, and a few 
> > in TAP directly to fill gaps (with intention to deprecate 
> > them when a definitive source is written: eg Time WCS paper 
> > and/or another rev of STC). Several values could be put 
> > together with dashes (as in STC Lib); someone could could 
> > plausibly (outside TAP spec) extend STC Lib with more useful 
> > constants so there is a nice picklist (and thus also used in 
> > the VOTable output, so this approach largely solves result 
> > metadata as well).
> > 
> 
> I am not very enthousiastic about this. Can we really not leave it out and
> for the time being leave it up to users to read the details of a given TAP
> service's schema? Imho TAP is too low-level to support the kind of automated
> interoperability  that seems to be foreseen in some of the use cases. For

I agree with Gerard's position on this.  I don't expect many cases
in which such metadata could/would be used in an automated fashion, 
so I don't believe that the additional complication, both in the 
TAP standard and for data providers, would be worth the effort.

Mark

-- 
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/