do something useful and simple first

[Ray Plante]

Hi Roy,

On Fri, 6 Feb 2009, Roy Williams wrote:
> Yes, OpenSkyQuery is excellent for crossmatch. However, I maintain that what 
> you can do there can be done easily as a two-stage process: first do 
> multicone for the rough crossmatch, then download the result to the desktop 
> and refine the result with further selections, using Topcat/Stilts. So 
> multicone gives us the ability to do crossmatch, and of course we can do 
> single-catalog query with existing facilities (eg Vizier). What else is 
> there?

You can certainly accomplish something useful with this technique; 
however, will this really scale?  If you want to do a massive 
crossmatch, do you have to essentially download entire databases?  An 
important innovation of OpenSkyQuery is a strategy for doing it 
more efficiently across distributed databases.

> What are the "many capabilities" you mention below?

Of course, the short-coming of cone search is that it only allows a single 
cone constraint.  You would like to extend beyond this to allow multiple 
cones.  We have in the past needed other constraints supported (the galaxy 
morphology demo needed a redshift constraint).  Any such variation on the 
cone search could be accomplished with TAP because it allows arbitrarily 
complex queries.

> There are already many versions of multicone out there (*). It is mainly a 
> rather simple question of standard formatting for the upload table 
> (RA,Dec,ID,radius for each). The version 2 standard could handle asynchronous 
> operation for vary large queries.
>
> Am I alone in this addiction to customer requirements and pragmatism? Am I 
> just being very short-sighted? Everyone else in this list is sure we need the 
> generality, complexity, and sophistication that TAP may provide eventually?

I wouldn't want discourage your idea.  If you see the need is urgent, I 
don't see why it can't be pursued in parallel with TAP.  Let's see a 
proposal and we can evaluate whether it makes sense to pursue it now. 
Then it becomes a question of whether it make sense to encourage the 
community to adopt it in advance of TAP.

hope this helps,
Ray