Expressing 2- and 3-D coordinates
francois at vizir.u-strasbg.fr
Wed Dec 14 09:40:02 PST 2005
>We already use arrays e.g. in SIAP
><FIELD name="naxis" ucd="VOX:Image_Naxis" datatype="int"
>The requirements which I would see as emerging are
>1) In the above example, FITS images can have >2 axes, e.g. additional
>frequency and polarization axes (which may have only one pixel, but that
>is not the point)
>2) For the Char model, some fields can either be a single value or a range
>(e.g. spatial resolution)
>- so can an arraysize be variable?
> * in any given VOTable? Or would it have to be set instance by
==> Yes, the arraysize attribute can specify variable-length
> * In the schema, to allow the case above?
==> In VOTable, there is no validation of the data -- but tools like
TOPcat can do this (and extremely efficiently!)
>At present, 4-axis images work fine in SIAP except that it ignors axes 3
>and 4 - but nothing 'breaks' so that's OK.
Francois Ochsenbein ------ Observatoire Astronomique de Strasbourg
11, rue de l'Universite F-67000 STRASBOURG Phone: +33-(0)390 24 24 29
Email: francois at astro.u-strasbg.fr (France) Fax: +33-(0)390 24 24 32
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