call for presentations at the Data Model sessions in Cambridge , September 2007

[Anita M. S. Richards]

On Tue, 22 Jan 2008, Doug Tody wrote:

>
> What is the point?  WMS involves heavy processing (interpolation,
> filtering, rendering) of the data onto a uniform grid, to make it
> well suited for efficient graphical display.  Usually extensive
> preprocessing is required.  It only works for heavily processed,
> survey type data.  There is no concept of discrete science datasets,
> e.g., images.  All the science-specific metadata required for
> scientific analysis is lost; there is no provision for providing this.
> For quantitative data analysis it is essential to be very careful about
> the data samples and associated metadata describing what they mean.
....
> for the part of VO which supports direct interaction with science
> data by users.  I think this is a much more important consideration
> for VO than support for advanced visualization, hence this is what
> should drive how we represent science data to client applications.
> We want to support advanced visualization, but that is secondary.

Yes indeed, and we want to avoid re-inventing the wheel.  We want to 
interface with advanced tools, not re-write them if possible, however much 
more fun it is than the more boring bits of developing VO standards. 
There is a scientific need for tools to image large areas of sky, such as 
for CMB work or to visualise large star-forming regions like the Orion 
complex.  However, I could not try and use these images to, say, estimate 
photometric redshifts! And when I am working on an individual 
protoplanetary disc in Orion which is perhaps less than 100 milli-arcsec 
across, the large scale tools and generic re-interpolation are not going 
to work.  However the most powerful argument is favour of VOTable is the 
ability to retain metadata including pointers to more detailed 
information, as Doug implied above.

cheers

Anita

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Dr. A.M.S. Richards, AstroGrid Astronomer,
Jodrell Bank Centre for Astrophysics, Alan Turing Building, 
University of Manchester, M13 9PL
+44 (0)161 275 4124
and
MERLIN/VLBI National Facility, Jodrell Bank Observatory, 
Cheshire SK11 9DL, U.K. +44 (0)1477 571321 (tel) 571618 (fax)