SIAV2 prototype / reference implementation

[Arnold Rots]

I would like to add something to Doug's message, regarding
event lists.
Just like filled data cubes are a special case of sparse cubes
(defined as a collection of sub-cubes within the frame of a
"master" cube), events lists are the other extreme: so
sparse that each individual voxel is listed separately.
They truly are multi-dimensional (usually at least 4-D)
images with a limited number of voxels called out individually.

Mark Cresitello-Dittmar developed a proof-of-concept prototype extension
of Doug's prototype that handles event data and provides cut-out
services, creating either event list subsets or n-D images - thus proving
the following concepts:
- The inclusion of event data is quite feasible and does not require
a great effort
- There is no reason to relegate event datasets to "pass-through" only
- It is feasible to integrate server-specific custom code as plug-in

The HEA community has been asking for the inclusion of its data
in the VO for several years. Event lists are well- standardized, but
the reactions has generally been that this must be too complicated.
Mark's proof of concept proves that this is not the case and that
there is no reason to exclude event list data from data cube
protocol development - or even to put off its inclusion.
Needless to say that adding HEA event data to the standard types
of data products in the VO greatly enhances interoperability.

Cheers,

  - Arnold





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Arnold H. Rots                                          Chandra X-ray
Science Center
Smithsonian Astrophysical Observatory                   tel:  +1 617 496
7701
60 Garden Street, MS 67                                      fax:  +1 617
495 7356
Cambridge, MA 02138
arots at cfa.harvard.edu
USA
http://hea-www.harvard.edu/~arots/
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On Fri, Sep 27, 2013 at 1:25 PM, Douglas Tody <dtody at nrao.edu> wrote:

> Hi DALers -
>
> If you want to try out the developmental/reference implementation of our
> SIAV2 prototype you can exercise the service yourself at the following
> link:
>
>     http://vaosa-vm1.aoc.nrao.edu/**ivoa-dal/siav2query.html<http://vaosa-vm1.aoc.nrao.edu/ivoa-dal/siav2query.html>
>
> This is just a crude Web interface used to test the prototype, but it
> provides an easy way to see how it all comes together.  The query
> response should render as a VOTable in your Web browser.
>
> In the current version the MODE parameter, used to enable cutout mode
> (and what I will be mostly focusing on in my talk in the DAL/DM session
> later today), is disabled.  While most of the functionality for this is
> implemented in the prototype service, it was not finished in time to be
> deployed to the demo service in time for this meeting.
>
> However the way it will work is simple enough: if for example one issues
> a query with "MODE=archival,cutout", the query response will be what you
> see now except that for each archival image for which a cutout is
> possible, there will be an additional row in the query response
> describing the cutout virtual image.  The metadata for the cutout image
> will describe the image that will be created if retrieved via the access
> reference.  No datalink is required in this case since the cutout image
> is described directly in the query response, and already has an access
> reference URL for retrieval.  All image retrieval, including retrieval
> of archival images as well as virtual image generation, is performed by
> the accessData request (the access reference URL returned in a query
> response is actually a call to accessData).  AccessData can also be
> called explicitly by a client to directly access a particular image
> identified by its publisher dataset identifier.
>
>         - Doug
>
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