Draft note on STC in the Registry

[Marco Molinaro]

Hi Markus, registry,

I'm a little more in favour of using NUNIQs, but given
the MOC orders in place, I don't consider this as a
critical thing.

If possible, can we have a more complex <spatial>
example in §2.3? Even at this early stage the single
cell there looks a bit too simple to exemplify what's
at stake.

Cheers,
    Marco

2018-01-28 17:46 GMT+01:00 Mark Taylor <m.b.taylor at bristol.ac.uk>:

> On Fri, 26 Jan 2018, Markus Demleitner wrote:
>
> > > In VOTables, an array-valued integer-typed cell can efficiently
> > > (for BINARY/2 serialization anyway) store MOCs in this form,
> > > and it should(?) be more straightforward for clients to ingest.
> >
> > I'm not awfully convinced as regards the compact representation -- the
> > ranges in ASCII are fairly nifty, and the All-Sky 0/0-11, at least,
> > is hard to beat.  And either way, I suspect it doesn't buy much
> > (like: factor of two) in the typical cases, in particular if you gzip
> > the VOTables.  However, we can just try it of MOCs we find in the
> > Registry, and I'd do that if there's sufficient interest.
> >
> > I'd consider the question of straightforwardness in handling much
> > more insteresting.  For me, where the database (at least for now)
> > accepts and supplies ASCII MOCs, ASCII is a lot simpler, more
> > human-readable, and reasonably nice in VOResource, so they appear to
> > me as more attractive in VOTable as.  But obviously NUNIQ wouldn't
> > require higher magic, either.
> >
> > When handling these things from C, I can absolutely believe that
> > NUNIQ arrays are highly preferable unless you have a nifty and
> > well-written library.
> >
> > So, I'm not sure and could be convinced either way.  Whatever we
> > do, I'd strongly suggest the serialisation should be the (within
> > reason) the same between VOTable (tabledata) and VOResource.
> >
> > Since I'd say this needs further discussion and possibly research, in
> > particular over on Apps, I've put it in as another question to
> > consider (Volute rev.  4717).
>
> OK well I don't have a strong opinion.  If the general feeling
> is that the ASCII representation is approximately as good or better
> than the numeric one, I won't push for a change.
>
> --
> 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/
>
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