handling metadata with multiple values

[Gretchen Greene]

This makes a lot of sense to me for readability and grouping of like
items and it would be great if there was agreement on how this is
handled to simplify metadata exchange between registries.

I also endorse the ucdList element and hope to see this added into the
VOResource schema.  This element would simplify mining metadata content
to find potential data sets which will satisfy data value driven query.
In other words a high level filtering capability.

 
-Gretchen

-----Original Message-----
From: owner-registry at eso.org [mailto:owner-registry at eso.org] On Behalf
Of Anita Richards
Sent: Tuesday, August 12, 2003 10:28 AM
To: registry at ivoa.net
Cc: Elizabeth Auden
Subject: Re: handling metadata with multiple values


Ah - in the AstroGrid Registry group we came to the opposite conclusion
-
that for human maintenance of the registry entries for data sets, at
least, it was easier for lists to be in container elements as it makes
it
much easier to see (in a properly indented document) where one
type of element ends and the next begins.
There are some exceptions at present for 'very important' elements with
short lists.

However you can call the items something more informative, for example

<ucdList>
  <ucd></ucd>
  <ucd></ucd>
  <ucd></ucd>
  <ucd></ucd>
</ucdList>

<instrumentType>
  <instrument></instrument>
  <instrument></instrument>
</instrumentType>

<coordinatePair>
  <coordinate></coordinate>
  <coordinate></coordinate>
</coordinatePair>

In the last example, I see that (if I understand correctly) the
Space-Time
metadata schemas from Arnold use a single type e.g.
"coord2ValueType"
to enter a pair of coordinates in a single element.  I can see many
advantages to that, but not all data may have both halves of the pair
or some queries may not care e.g. all data above dec -20 - will this be
more complicated to impliment in a search than if (say) RA and Dec were
separate elements?

thanks
a
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Dr. Anita M. S. Richards, AVO Astronomer
MERLIN/VLBI National Facility, University of Manchester,
Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL, U.K.
tel +44 (0)1477 572683 (direct); 571321 (switchboard); 571618 (fax).