STC in VOTable: Time utypes

[Gerard]

Dear Arnold and others

> From: Arnold Rots [mailto:arots at head.cfa.harvard.edu]
> Sent: Tuesday, April 13, 2010 9:29 PM
> Subject: Re: STC in VOTable: Time utypes
>
> I have no great love for substitution groups myself; anyone who has
> implemented themcarries the battle scars.
Good to hear that.

> But finding an alternative that is effective is a project for STC
> version 2.
I suppose that is true, maybe we can start this as I suggested (pushed
somewhat by Markus).

> At this point we are trying to find a way to express version 1 in
> utypes, and that means having to deal with substitution groups.
> 
My point is that we should do our best to work around substitution groups
wherever they appear.
In particular we should not adapt the definition of utype-s to be able to
deal with them.
As UTYPEs are supposed to point into a data model, not into a schema, is it
possible to identify the STC data model without referring to the STC-X
implementation? I guess the document at
http://www.ivoa.net/Documents/REC/DM/STC-20071030.html defines all concepts.

Would it be possible to create a table of STC utypes that point to the
appropriate section in this document that defines the corresponding concept?
(this might make Norman happy as well).

Cheers

Gerard

> Cheers,
> 
>   - Arnold
> 
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> ---
> Arnold H. Rots                                Chandra X-ray Science
> Center
> Smithsonian Astrophysical Observatory                tel:  +1 617 496
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> arots at head.cfa.harvard.edu
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