new characterization schema: STC Concerns and Proposal

[Arnold Rots]

When I asked yesterday why Characterisation wasn't using higher-level
structures from STC, I was actually serious and even more so after
Anita's presentation and some of the concerns that Igor voiced.
I realized that the Characterisation schema is going through the same
issues now, that I went through in the development of the STC schema,
in terms of required axes, elements, and references.  It seems
unnecessary to have to rehash all of that again.
In particular, by rebuilding the STC-related elements from lower level
STC components the integrity of the coordinate metadata in the related
axes is lost and it will be a major effort to regain it.
The thing is that all of the axis-related stuff in Characterisation is
contained in the ObsDataLocation element in STC, with the exception of
sensitivity.  It would be a rather simple thing to add the sensitivity
concept to stc:AstroCoordArea.  When that is done you would have a
complete implementation of the axis-related characterisation in
stc:ObsDataLocation, complete with all the proper structure and added
value in a fully implemented referencing mechanism.
It is easy to see that Anita's example would be completely represented
in this - I'll provide an example of it next week.

I am not proposing any change in the Characterisation _model_, only in
the XML schema implementation by simply plugging in ObsDataLocation
which is a ready, complete, and tested element.
Note that this same ObsDataLocation element is also used in the
VOEvent schema.

I know that the organization of the information is different - the
matrix is transposed, so to speak.  But that was done to facilitate an
easier implementation of the related coordinates.  And it is only a
matter of code: it should not be harder to present the information in
a transposed view.

And I don't think it would delay the process, either.  As I said, the
model (and hence the WD) is not affected, while the schema development
will be easier since all coordinate concerns are taken care of.  I
promise to add the sensitivity components right away to STC since it
does not seem like that will be difficult since I should be able to
take it from the current Characterisation schema.

Cheers,

  - Arnold

Francois Bonnarel wrote:
[ Charset ISO-8859-1 unsupported, converting... ]
> 
> Hi all,
>    Version 0.95 of the characterization xml schema (axis first) is available
> following this link :
> http://Model/Characterisation/schema/characterisation.0.95.xsd
>   It has been properly validated, importing stc1.3 schema and using
> xmlspy. So it could be possible to use it to develop validated examples.
> 
> Best regards
> Fran?ois
> 
> =====================================================================
> Francois   Bonnarel               Observatoire Astronomique de Strasbourg
> CDS (Centre de donnees          11, rue de l'Universite
> astronomiques de Strasbourg)    F--67000 Strasbourg (France)
> 
> Tel: +33-(0)3 90 24 24 11       WWW: http://cdsweb.u-strasbg.fr/people/fb.html
> Fax: +33-(0)3 90 24 24 25       E-mail: bonnarel at astro.u-strasbg.fr
> ---------------------------------------------------------------------
> 
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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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