Generic FIELD/PARAM metadata items in VOTable

[Mark Taylor]

On Fri, 19 May 2023, Molinaro, Marco wrote:

> I'm wondering how or whether the key/value, or
> property/content, would be advertised to the client
> or documented.
> Or would this be to allow custom or dedicated
> server-client interaction only?

Not all clients would be interested in this information, and they
could certainly ignore it harmlessly.  In the case of STIL its
internal table model has space for miscellaneous per-column metadata,
and this would show up in topcat for instance as an additional
displayed column the Columns Window alongside units, UCD and the rest,
for each key that's present in any of the columns
(http://www.starlink.ac.uk/topcat/sun253/ColumnInfoWindow.html).

In other cases clients might go looking for specific items and
make use of them as appropriate, but I'd expect the documentation
for such items would exist outside of VOTable, for instance
in other standards or in service-specific documentation.

The option to include miscellaneous per-column metadata is already
present in other formats like ECSV, IPAC and arguably FITS, and
I guess clients have already figured out how to treat, or ignore,
those items as they wish.

Mark

--
Mark Taylor  Astronomical Programmer  Physics, Bristol University, UK
m.b.taylor at bristol.ac.uk          https://www.star.bristol.ac.uk/mbt/