TAP, skynode, or boutique?
dtody at nrao.edu
Fri Sep 5 08:56:35 PDT 2008
Hi All -
As Guy points out, we plan for TAP to include support for
multi-position queries, with no inherent limits (unlike SkyNode)
on either the number of positions or the size of the tables/query
Using POS/SIZE will provide a basic spatial cross-match capability.
More sophisticated cross matching applications could do such a simple
spatial cross match as the first pass, then possibly refine the cross
match using additional non-spatial object attributes. But the basic
capability will be simple and fully scalable.
On Fri, 5 Sep 2008, Guy Rixon wrote:
> quoting from the TAP/PARAM draft that was current before the Trieste meeting:
> 3.3.6 Multi-Position Queries
> A multi-position query generalizes POS, SIZE to a table of positions,
> allowing an
> arbitrarily large number of spatial position-based queries to be executed
> simultaneously. In a typical scenario the user uploads a list of the
> positions of
> their favorite objects, and executes a spatial cross match against some data
> table. The multi-position query provides this simple spatial cross match
> (full text at http://www.ivoa.net/internal/IVOA/TableAccess/tap-v0.2.pdf)
> Unless the NVO people working on this have found problems, this is still to
> be part of the initial TAP spec (we'll find next week when we start to edit
> the proposals into a unified draft).
> Therefore, I would expect that you might be able to use TAP installations for
> cross-match sometime this year with prototypes and next year with production
> On 5 Sep 2008, at 16:14, Roy Williams wrote:
>> Dear DAL WG
>> I am writing to ask if the Skynode protocol will continue to be supported
>> in the broader IVOA. Most of the current implementations seem to be at
>> Johns Hopkins University -- is that true? Are there other skynodes out
>> there that are and will be properly maintained?
>> A group of us in US-VO are developing an application (Vim) that handles
>> multiple sky positions by running proximity (cone) searches against
>> published catalogs. Thus a single click of the mouse can cause execution of
>> a thousand separate cone searches against a single server. This can be very
>> slow, and we would like to scale things up. We want a crossmatch service --
>> by which I mean no more than multiple cone searches. We want to do a
>> thousand or a million cone searches in one "crossmatch" request.
>> Which of these paths should the Vim team follow:
>> (1) After years of discussion in this WG, I am still not seeing the
>> emergence of anything like simple crossmatch in the TAP specification. So I
>> guess we are still more years from widespread, solid implementation of TAP
>> that can do crossmatch. Is that true?
>> (2) The Skynode protocol can do crossmatch already, and I wonder if this is
>> the direction the Vim team should follow instead of waiting for TAP.
>> However, before doing this, we would really like an assurance that there
>> will continue to be multiple organizations supporting Skynode!
>> (3) The third way to get fast crossmatch would be to look through all the
>> data center web pages looking for their own crossmatch services (eg
>> ), and then build a custom interface from Vim to each data center.
>> Thank you for your help
>>  http://cas.sdss.org//dr6/en/tools/crossid/upload.asp
>>  http://irsa.ipac.caltech.edu/applications/Gator/GatorAid/Gator_Api.html
>>  http://vizier.cfa.harvard.edu/viz-bin/vizHelp?file.htx
>> California Institute of Technology
>> 626 395 3670
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