Request to add some parameter types to CEA schema

[Paul Harrison]

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