Licence of VO-DML files?

[Markus Demleitner]

Dear Laurent,

On Wed, Nov 04, 2020 at 05:18:28PM +0100, Laurent Michel wrote:
> I’ve a question: 
> What is exactly covered by a licence on a e.g. VODML file, the
> content of the structure?

Licences use copyright, not (centrally) patents -- hence, it's a
concrete sequence of bytes that the licence covers rather than an
abstract arrangement of boxes and arrows (which patents could cover,
but let's make sure we steer clear of any such considerations; we're
all to poor to be able to deal with patents).

> The VODML standard is under
> http://creativecommons.org/licenses/by-sa/4.0/
> <http://creativecommons.org/licenses/by-sa/4.0/> The VODML XSD is a
> part of the standard, therefore it is also  under
> http://creativecommons.org/licenses/by-sa/4.0/
> <http://creativecommons.org/licenses/by-sa/4.0/> Can I licence a
> VODML file, issued from that XSD, with any licence?

As far as I know, we don't have any actual licence statements yet, do
we?  When these come, they will need to say what they cover.  Now, if
we want to do it really well, it will become unnecessarily complex
(e.g., ivoatex right now is under GPL, and when you derive your
architecture diagram, in our current licence plan the bytes
transition from GPL to CC-BY-SA, which would be a lawyer's
nightmare).

Since I didn't succeed with my plea for CC-0 throughout (which I'd
then also extend to ivoate), let's keep it cavalier.  The standard
licence statement for standards should say "Unless specified
otherwise in the material, this standard and any ancillary files
distributed with it are Copyright 2020 by the IVOA Executive
Committee (or whoever), licensed under CC-BY-SA [url, perhaps a bit
more blurb]."

Then, the VO-DML file would have an XML comment saying something like

  Measurement DM -- machine readable data model for distributions
  resulting from measurements

  Written 2020 by...

  This file is made available by the IVOA under the CC0
  Public Domain Dedication,
  http://creativecommons.org/publicdomain/zero/1.0/

All that isn't terribly bullet-proof on the legal side, but I suppose
it's going to be sufficient to safely be able to distribute the
material (and get it past the Debian ftpmasters, who are generally
happy if the intentions are clearly discernable).

        -- Markus