On 2007-10 -08, at 14:26, Guy Rixon wrote:
> Hi,
>
> recent work with CEA v1 (the AstroGrid one) reveals a need for some
> extra
> parameters types. Specifically we need a Table type that is less
> specific than
> VOTable. We need this to cover DSA where the output is always a
> table but can
> be in any of three formats. Similarly, Image would be a useful
> type, more
> useful than "FITS".
>
> This need persists into CEA v2 and UWS-PA.
>
The current CEA v2 proposed schema has the following as parameter "types" - (see the ParameterTypes definition in http://www.ivoa.net/ internal/IVOA/CommonExecutionArchitecture/CEABase.xsd)
integer
real
complex
text
boolean
anyURI
VOTable
angle
MJD
DateTime
ADQL
ADQL-S
STC
STC-S
binary
FITS
XML
So I think that CEA parameter "type" can probably be thought of a
sort of serialization using the vocabulary of the DM group - but
this has always been a slightly fuzzy concept in CEA - and the above
list is probably not entirely self consistent - the main driver for
this "typing" was to give hints to the User Interface on how to form
the content of the parameter (e.g. an ADQL widget to help with
forming adql queries). Each parameter has the possibility of being
further defined by UCD and UTYPE, which for instance allows angle to
be subtyped into RA.
I would have no problems with adding Table and Image as types (and perhaps Spectrum?), but perhaps it would be a good idea to review this whole area to see if there are any more useful classifications. - or perhaps the serialization needs to be a separate concept (so FITS and VOTable) do not belong in the above list,. Maybe review the currently used PLASTIC messages, as they have a similar purpose of being suggestive rather than prescriptive about what is actually being passed around...
As a final point - in the future what will DSA have to do with CEA2 (i.e. UWS-PA)? surely this will be pure TAP...(which will include its own UWS)
Dr. Paul Harrison
JBCA, Manchester University
http://www.manchester.ac.uk/jodrellbank
Received on 2007-10-10Z19:56:25