[Voevent-core] Fwd: standard vocabulary

[roy at cacr.caltech.edu]

Thank you for making this point Tony. There is a distinction between UCD
semantics (content description) and UCD syntax (combination of word
hierarchies) that should be made explicit.

> I've always seen UCDs as like data types. They are applied to columns and
> describe what type of data is in the column - so they are data types. Much
> the same as 'float', which I guess you could call number.float;32bit

Yes. That is the right way yo think of UCD.

>  In which case GRB is not really relevant as a UCD, nor is
> process.variation.burst;em.X-ray.

We are trying to be careful to talk of "controlled vocabulary" and "UCD
syntax". Your example is not a datatype or a UCD. Rather it is a piece of
controlled vocabulary expressed in a UCD-like syntax.

> So unless UCDs are now going to be turned into the new astro thesaurus or
> a type of astro ontology, it doesn't seem to make sense to have a UCD for
> GRBs.

Thesaurus and Ontology imply a set of nodes and relations between them. At
the moment we are just building the nodes, i.e. the controlled vocabulary.
We could in the future build more structure.

Roy