VOTable session @ Interop.Moscow

[Mark Taylor]

On Thu, 21 Sep 2006, Rob Seaman wrote:

> On Thu, 21 Sep 2006, Bob Mann wrote:
> 
> >>> An astronomer wants to cross-match sources in catalogue  A with  
> >>> objects in catalogue B using an algorithm which cannot be  
> >>> executed inside either database or as part of an ADQL query. She  
> >>> runs a conesearch (or equivalent) on each database, to extract  
> >>> the entries from each lying in the area of sky in which she is  
> >>> interested, and obtains two VOTables, votA and votB. She passes  
> >>> these both to her cross-matching service, which returns a VOTable  
> >>> recording pairs of entries in votA and votB which her algorithms  
> >>> judges to be safe matches.
> 
> On Sep 21, 2006, at 7:14 AM, Mark Taylor wrote:
> 
> >> your use case is certainly a reasonable one, but I'd say the way  
> >> to tackle it is simply to insert an identifier column in each  
> >> table, containing the same tag as you would have put in the TR ID  
> >> attribute.
> 
> On Sep 21, 2006, at 7:49 AM, Roy Williams wrote:
> 
> > They said over and over that the VO is too complicated and too much  
> > jargon and not enough astronomy.
> 
> I suspect that this will turn out to be one of the most frequent VO  
> use cases.  It has certainly recurred over-and-over in the past with  
> each new sky survey.  A typical survey opens up new vistas of phase  
> space.  For this new territory to be useful, it must be marked with  
> IDs corresponding to previous catalogs resulting from previous  
> surveys.  The cross-matching can be as valuable as the new  
> observations.  The key point is that the cross-matching should be  
> done with astronomically meaningful IDs, not just indices into  
> databases.  For just one reason, because VO users will continue to  
> use non-VO tools – including perhaps, gasp!, the published literature  
> – that will have astronomical IDs.

Fine, good idea, I'm sure that's true.  But you can do it all using
existing constructions (add a new column containing ID values, ideally 
astronomically meaningful ones), it doesn't need any change to the 
VOTable schema.

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/