new characterization schema: STC Concerns and Proposal

[louys at alinda.u-strasbg.fr]

Dear Arnold,

My first impression is that your suggestion would impose an overhead in 
the characterisation strucure , because each characterisation item , at 
the 1-2 levels will have to point to the ObservationLocation structure 
which means one added level of indirection.
I would really prefer to use the STC structures in an object oriented 
way , that is encapsulating STC elements.

we 'll work out examples on instance documents, to check for the 
feasibility of your approach in our context.

cheers, Mireille

Quoting Arnold Rots <arots at head.cfa.harvard.edu>:

> 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
>> ---------------------------------------------------------------------
>>
> --------------------------------------------------------------------------
> 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/
> --------------------------------------------------------------------------
>