More VOTable 1.2 points

[Mark Taylor]

Francois and others,

I have some additional points to make about the VOTable 1.2 document.

Examining the VOTable 1.1 and 1.2 schemas, I have found a few
differences which are not documented in Section 8 "Differences between
versions 1.1 and 1.2":

  1. The VOTABLE and RESOURCE elements now permit a GROUP to appear as
     a direct child.  This is probably reasonable in order to group
     PARAMs which are already permitted there, but this change should
     be documented in section 8.

  2. The TABLE element now permits multiple DATA elements.
     I can't see this is a good idea - I presume it's a mistake
     in the schema.  Should be corrected.

  3. The TR element has acquired an ID attribute.  A comment in the
     schema notes:

        "The ID attribute is added here to the TR tag to avoid
         problems of code generators which do not properly
         interpret the TR/TD structures"

     I am not very keen on introducing otherwise unwanted features in
     a schema to pander to the vagaries of poorly written third
     party code.  There should at least be a debate about whether
     this is a distasteful but pragmatic necessity for the VOTable
     schema, or whether it should be the responsibility of those
     using code generators to work round said problems (I'm not
     sufficiently knowledgeable about the use of code generation
     to have a firm opinion, though I can supply prejudices on
     request :-]).

     At the very least, if this attribute is introduced, it must be
     documented in section 8.

There is also another item I've just noticed, which it seems was
introduced in the 1.1 schema:

  4. The TD element has an "encodingType" attribute.  This seems to be
     related to the idea proposed in Appendix A.5 "Encoding individual
     table cells".  That appendix describes an idea which was discussed
     but never agreed for introduction into the standard.  Nowhere in
     the body of the document is the meaning of this attribute for a
     TD mentioned.  I therefore believe it should never have been
     introduced, and should be removed.

Mark

-- 
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/