Re: [Plastic-devs] spectrum messaging

[Mark T. <m.b...@br...>]

On Fri, 8 Sep 2006, John Taylor wrote:

> 
> 
> Isa Barbarisi wrote:
> > Hi all,
> > sorry for my silence on this but I was on leave.. :-)
> >
> > Noel is right, currently VOSpec implements an old version of Plastic 
> > where the list of supported messages was left empty, this to indicate 
> > "all messages".
> >   
> Perhaps, I should have made the hub still support this "mode" for older 
> versions of the spec, but felt that since the Plastic community is still 
> relatively small it would be OK to ask people to update.  Apologies if 
> this has caused you any inconvenience.
> > We have managed to send spectra from VOQuest to VOSpec by the 
> > ivo://votech.org/votable/load message, sending the votable as String 
> > argument. And I can also send/receive spectra from Topcat&Others using 
> > the same messages, votable/load and votable/loadFromURL, getting the 
> > arguments and calling our internal methods to visualize them in VOSpec.
> > So no spectra messages have been used in VOSpec and this was kind of 
> > working around the issue.. so I'm actually happy to know about the 
> > beginning of this discussion, so that I could update the plastic 
> > implementation in VOSpec for spectra transfers, hopefully in the next 
> > release before Moscow.
> >   
> Then we'll have to work quickly.  We've had some discussions here at the 
> VOTech meeting (pity you couldn't make it!) and Mark is going to post 
> the ideas on the wiki soon.

Isa,

As John said, we discussed this in Strasbourg.  The conclusion 
seemed to be that the best thing would be to introduce a new
message with the semantics "load spectrum", with an additional 
arguments specifying the format (VOTable, Spectral Data Model FITS 
serialization, 1-d FITS array, ...) that the data was in.

This is not the approach that we've taken with previous messages, 
which have concentrated on the data format (VOTable, FITS) rather 
than the data semantics (source catalogue, 2-d image).  However,
spectra/SEDs seem in practice to be a bit different in that there 
are many different ways that they can be serialized.  So for 
pragmatic reasons I think this is the best way forward.
I'm planning to write a draft definition of such a message on
the wiki shortly.  However, if you disagree with this approach,
please post your arguments here shortly.  Incidentally, what 
formats can VOSpec load spectra from?

Mark
   
-- 
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b...@br... +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/