SLAP-1.0 Erratum 1: No em.line in a primary position

[Markus Demleitner]

Dear DAL,

During a global validation of UCDs it was found that the SLAP
standard requires the use of the UCD "em.line", which is invalid by
the UCD standard.

After some deliberation which standard ought to give, the Semantics
WG found that SLAP should, as em.line really is qualifier ("of a
line") and changing that would have operational consequences, whereas
fixing the UCD in SLAP does not (as SLAP clients use utypes and there
are very few SLAP services anyway).

Hence, after consultation with Mireille I am proposing
https://wiki.ivoa.net/twiki/bin/view/IVOA/SLAP-1_0-Err-1

If there are comments, questions, or suggestions for improvement,
I'd suggest the discussion should take place on the DAL list.

Thanks,

          Markus