Referencing STC in VOTable: IDREF problem

[Mark Taylor]

Francois,

yes, either of these would work, though they (unavoidably?) complicate
the mechanism even further.  I agree with you that your option (2) is 
much the preferable of the two.

Mark

On Tue, 14 Oct 2008, Francois Ochsenbein wrote:

> I see essentially 2 (easy?) solutions which could work:
> 
> 1. Use Arnold's proposed way with
>    xlink:href=ivo://STClib/CoordSys#UTC-ICRS-TOPO" and
>    xlink:href=ivo://STClib/CoordSys#UTC-ICRS-TOPO",
>    as it is used in VOEvent; it requires an additional
>    namespace (and is not always understood by validators)
>
> 2. Specify the frame in a parameter with
>    utype="stc:AstroCoords.coord_sys_id"
> 
> The alternatives would look like:
> 
> 1. xlink usage:
>     <GROUP ID="Coo1" utype="stc:AstroCoords"
>       xlink:href="ivo://STClib/CoordSys#UTC-ICRS-TOPO"
>       xlink:type="simple">
>       <FIELDref ref="RAJ2000"/>
>       <FIELDref ref="DEJ2000"/>
>       <!-- etc -->
>     </GROUP>
>     in the first example,
> 
> 2. Specification via the "coord_sys_id" of the STC schema:
>    <GROUP ID="Coo1" utype="stc:AstroCoords">
>       <PARAM name="cooframe" datatype="char" arraysize="*"
>          utype="stc:AstroCoords.coord_sys_id"
>          value="UTC-ICRS-TOPO"/>
>       <FIELDref ref="RAJ2000"/>
>       <FIELDref ref="DEJ2000"/>
>       <!-- etc -->
>    </GROUP>
> 
> Although I would prefer the 2nd alternative (full compatibility with
> the VOTable schema without additional namespaces), I'm open to
> other opinions...

-- 
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/