Anita,
by my reading of the SSAP spec, the position encoding is part of the Spectrum data model:
Coverage.Location.Sky.Value pos.eq RA and Dec deg, R (or sexagesimal string)
If I understand this correctly, each column of the VOtable returned by SSA is a node in the Spectrum data model, with an associated Utype. This position node is defined as a coordinate pair, so the column isn't a scalar, numeric type. It would have to be either a string or an array of float or double. Would the array form work for you? I guess the string form covers the case where the coordinates are sexagesimal.
Cheers,
Guy
On 1 May 2007, at 17:07, Anita M. S. Richards wrote:
>
> Hi people,
>
> Today we were doing a demo at the E-Science North West open day in
> Manchester and someone asked 'can you display the positions of
> spectra on top of images'. So I used AstroScope to get some
> spectra and images and sent an image to Aladin, and sent the SSAP
> VOTable to Aladin and TopCat. Two problems emerged:
>
> The position is given in decimal degrees but type is string. If I
> change to float, TopCat will plot the positions.
>
> However, even then, Aladin will only offer to display it in a
> spectral tool - it won't plot the positions.
>
> Probably we ahve discussed this and there are good reasons for it
> not working? Or is it something to do with retrieving SSAP stuff
> via AstroScope? But otherwise, it seems easy to fix and would
> please users.
>
> Thanks
>
> Anita
>
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> - - -
> Dr. Anita M. S. Richards, AstroGrid Astronomer
> MERLIN/VLBI National Facility, University of Manchester, Jodrell
> Bank Observatory, Macclesfield, Cheshire SK11 9DL, U.K. tel +44 (0)
> 1477 572683 (direct); 571321 (switchboard); 571618 (fax).
Received on 2007-05-04Z17:52:23