Single or collection resources

[Robert Hanisch]

Hello, Markus.  My preference would be for option 2.

The resource metadata was intended to describe a data collection, e.g., data
from a particular instrument, of a particular class of objects, or
pertaining to some phenonemon.  In cases where the metadata elements are not
unique for the collection (your example of CREATOR) it is perfectly ok to
use values like "Various".  The metadata for data collections is supposed to
aid discovery, not be a full description of each and every image in the
collection.  The FITS keywords for the individual files should contain
additional metadata specific to each image.

I agree that having the same data served through multiple services is likely
to confuse users.  And we don't really want an explosion of SIA services,
each with a separate registry entry.

Bob


On 8/4/09 7:22 AM, "Markus Demleitner" <msdemlei at ari.uni-heidelberg.de>
wrote:

> Dear DAL folks,
> 
> here is a somewhat "soft" question for a change:
> 
> I have various image sets, all of them small-ish or medium sized
> (i.e., several 100 to a few 10000s of images); some of them can be
> grouped "thematically", e.g.,
> 
> * Ancient plate scans from various observatories
> * Images of gravitational lenses from various observatories
> 
> I can see three strategies to publish them via SIAv1 (disclaimer: I'm
> not really up to date on SIAv2 discussions; but then I'd like to have
> a short-term, SIAv1-based solution anyway):
> 
> (1) provide a SIA service for each data set individually
> (2) provide SIA service for each "topic"
> (3) do both.
> 
> Now, (1) is nice because it lets me specify meaningful RMI-style
> metadata (creator, source, etc), so things will look nice in the
> registry and users have a fair chance to read up on where the data
> actually came from.  Downsides of this include that I'll clutter up
> result displays in VO-wide Astroscopes  and similar applications, and
> clients will have to issue potentially quite a number of queries to
> my server with all the incurred overhead.
> 
> (2) is attractive because people interested in, say, gravitational
> lenses would have to query just one service on my server and get
> everything I have.  But the metadata will be extremely ugly ("creator:
> various"), and as far as I can see, SIAv1 does not provide a standard
> mechanism to say something like "RMI metadata for this row can be
> obtained here".
> 
> (3) could be a solution, giving rich metadata on the services but
> still providing a service giving people all pertinent information in
> one go.  But of course I'll still clutter up Astroscope and friends,
> and even worse, each result will show up twice, once in the
> collection service, and once in the individual services.
> 
> So, I think there's no ideal solution -- but maybe others have
> better ideas or at least opinions on what a good VO citizen should
> do?
> 
> Cheers,
> 
>         Markus