TAP into TOPCAT

[Mark Taylor]

Hi all,

I'm working on a TAP client for TOPCAT.  This is not yet 
ready for public release, but it's working well enough to play with.
I think at this stage it is worthwhile to make a pre-release version 
available to interested parties, especially to TAP service implementors 
and hosters.  Hopefully this can help both sides: in particular
by examining what doesn't currently work we can identify what needs
to be fixed or improved on the client or server side or both.

You can find a copy (which may be updated without warning as I work
on it) at:

   ftp://andromeda.star.bris.ac.uk/pub/star/topcat/pre/

Find the TAP load dialogue in the VO menu or the Load window.
The TAP functionality is currently undocumented, but I hope it's
reasonably clear how to drive it: first either query the registry
for TAP services and then select one, or type the TAP service URL
directly into the field at the bottom.  Then go to the Enter Query
tab where you can examine the table metadata as provided by the
service, and type an ADQL query.  The OK button at the bottom starts 
the query running, and some rudimentary details about it can then 
be seen in the Running Jobs tab.  When the job completes the
resulting table gets loaded into TOPCAT.

Table upload is supported: just use the table identifier "TAP_UPLOAD.T3"
for the table with ID 3 (the one labelled "3: something-or-other" in
the main control window).

There are STILTS clients included here too: see comands tapquery and 
tapresume (ftp://andromeda.star.bris.ac.uk/pub/star/stilts/pre/
includes limited documentation).

Of the currently registered TAP services, the only one TOPCAT seems 
to work well with currently is the GAVO one (though at time of writing 
that service is uncharacteristically not responding).  Note that 
only the AstroGrid registry is currently capable of responding to
queries for TAP services.

I'm more than happy to talk to TAP implementors or service providers 
about the details of how their particular services do or don't work 
with this client and figure where problems lie (I already am talking 
to some of you, and others may hear from me sometime soon).

Comments on the user interface and functionality are welcome too,
though I know that this is currently deficient and I already have
a list of improvements that I know need making before public release.

I've cross-posted this to the DAL and Apps lists; I suggest that
any follow ups to this message are either to me or to one or other 
(rather than both) of those lists as appropriate.

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/