new take on resource registration best practice

[Ray Plante]

Hi RWGers,

At the IVOA meeting in Hawaii 
(http://wiki.ivoa.net/twiki/bin/view/IVOA/InterOpSep2013Registry), the 
Registry Working Group continued its discussion of a unified 
convention/best practice for registering data collections and their 
services.  In particular, Markus Demleitner raised a significant issue 
with a proposal we've discussed for some time and I outlined 
explicitly in Heidelburg.  This led to some rethinking about the best 
way to register collections.

In short, that previous proposal recommended that if you had a 
collection of data to register, you would register it first as a 
DataCollection (and include all the science metadata), and then you 
would register the services that access that collection as separate 
resources.  Markus, in his presentation, showed that this led to some 
really messy, hard-to-construct queries using RegTAP.  

We had some breakout discussions to consider a different approach that 
would allow for simpler queries.  A leading idea was to register a 
data collection and all the services that access it as a single 
resource (with multiple capability elements).  

I would like to open up this discussion generally (particularly for 
those who could not attend the Interop).  I've create a twiki page, 
http://wiki.ivoa.net/twiki/bin/view/IVOA/RegisteringBestPracticesDisc, 
that tries to summarize the issue and lay out this new proposal for 
registering data collections and their services.  There is a question 
as to whether the CatalogService resource type is sufficient for 
registering collections in this way or whether a new resource type 
(which looks more/less like a CatalogService) is needed.  The page 
also examines various typical and special cases.

Please offer any comments either via the mailing list or as additions 
to the RegisteringBestPracticesDisc page.  (If you do the latter, you 
might ping the rest of us with a quick note to the list saying that've 
made updates.)

cheers,
Ray