VOResource v0.8.2

[posuna at iso.vilspa.esa.es]

Hi all,

in fact, we have had discussions on these issues about UCDs at the UCD
steering commitee, and I would suggest that we wait until Roy Williams
(the UCD group chairman) starts his working day in the States as he
would be the best person to give you a summary on all our discussions.
This would save you some time on guessing .....

Cheers,
Pedro.



On Fri, 26 Sep 2003 10:46:26 +0100 (BST)
Anita Richards <amsr at jb.man.ac.uk> wrote:

> 
> On Fri, 26 Sep 2003, martin hill wrote:
> 
> > I shall take this opportunity to raise my own pet peeve: UCDs are
> > not nearly enough for describing data properly, so that we can
> > compare and combine data across different datacenters.
> >
> > But the registry does need one (or several) ways of describing data
> > using a common 'dictionary' of some sort, and UCDs are the best
> > we've got right now!  It may be that not every column needs to be
> > assigned a UCD (? what do people think? ) but the ones that
> > astronomers are likely to query on (the WHERE part of an SQL clause)
> > will need them.
> 
> Yes indeed...
> 
> As I understand it UCDs were evolved to aid catalogue _selection_
> (before services were available to manipulate much of the data inside
> catalogues) and thus they are very well suited to registries. For
> example there is a UCD for 'time' but it does not tell you if it is
> the start or stop time. This is fine for the Registry to select
> catalogues which might be used to plot a time series for an object. 
> Do we need separate UCDs for start and stop times etc? As Martin
> suggests, that should be decided by looking at existing science
> problems to see what would be useful and what is a priority.  But
> isn't that more a VOQL issue than a registry issue?
> 
> cheers
> 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).
> 
> 


-- 

Pedro Osuna Alcalaya


SOFTWARE Development Group
XMM-Newton Science Archive				
e-mail: Pedro.Osuna at esa.int
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