Preview UCD?

[Markus Demleitner]

Dear Semantics WG,

I'd like to add columns containing previews to my "product" tables
(i.e., for SSAP, SIAP, ObsCore), and I'm looking for an easy way to
convey their location to clients, ideally independent of the actual
protocol.

After a very short deliberation, I decided that having a UCD for
previews would be the simplest way to do that.  This could be
meta.preview or maybe even meta.ref.url;meta.preview.

In conversations with Sebastién and Mireille we realised that doing
such a thing raises the question if we shouldn't use the opportunity
to allow more specific metadata to be conveyed on meta.ref.url in
other cases, too -- e.g., there's a case to be made that clients
should be able to tell an accref apart from a service access URL
based the UCD of the element it's encountered in.

At that point I realised that this path of thought leads to what we
are currently producing in datalink, where there's an "official"
vocabulary for kinds of data products (a source is at
http://volute.googlecode.com/svn/trunk/projects/dal/DataLink/datalink-terms/src/datalink-terms.csv;
this exists in some RDF serialisation somewhere, too).

And then the question is if that vocabulary couldn't be leveraged for
a fine-grained description of meta.ref.url, maybe by defining a data
hierarchy that would have terms from that vocabulary.  My preview UCD
would then be meta.ref.url;data.preview, say.

So -- what do people think?  Is preview a special enough case to just
add meta.preview?  Is the utility of being able to say what kind of
product a table column links to big enough to try the inclusion of a
UCD-external vocabulary?  Is there another UCD-based way to do what I
want?  Or would this be a case for annotation based on LINK?

Cheers,

        Markus