3D data model

[Doug Tody]

Francois -

I certainly don't think a new WG is needed, rather we should start to
look at how to deal with 3D data within DM and DAL.  Currently this is
more of a discussion topic than anything else.  While we don't know yet
what is required to address the general problem of 3D data, it is clear
that it is closely linked to image and spectral data access and we should
take this as a starting point.

The Characterization model is supposed to apply to any VO dataset which
should include 3D data.  All it does though is physically characterize
the dataset in terms of bandpass, sampling, resolution, etc.  - there are
many issues of access to 3D data which this model alone will not address.
But we would like to use the standard characterization model for all data
including 3D data.

The Euro3D effort is very interesting, I was not aware of this.  This looks
like it could help greatly to define from the data analysis side what
is required to deal with 3D data.  My main concern is that it appears to
deal mainly with O/IR spectroscopic instruments (IFU, MOS, Fabry-Perot,
etc.) but we need to consider spectral data cubes as well, e.g., from
radio or from multiband surveys.

	- Doug