[CATALOGUE]Starting Data Model Subgroup

[Matthew Graham]

Hi,

> A catalogue is not a table, generally speaking.  It can be expressed 
> as a table or as a set of many tables, but that is not the point.  
> A catalogue is a set of derived data: derived from imaging, spectral, 
> event lists, time series, interferometric, or other types of data.
> The data model must describe not only the structure of the "table", 
> including attributes and values, but also inheritance, provenance,
> semantics, error columns, and more (units, formats, column-column 
> relationships, table-table relationships).  

This really just sounds like defining the VOTable superclass. If there is
more to it than that might I suggest changing the name of this DM from
Catalogue to Derived Data Set or something similar because when I think of
a catalogue, I think of a tabulated structure, be it for books in my local
library or lingerie from Victoria's Secret.

	Cheers,

	Matthew