[TAP] data type for column metadata

[Patrick Dowler]

On 2009-03-31 16:37:08 Douglas Tody wrote:
> But refsystem/refposition/flavor ("flavor" is awful) would only be
> used by coordinate-type columns - for many other table columns they

Yes, these are additional metdata to understand coordinate values, but also 
redshifts in catalogues. For the most part they would not be needed.

> would not be used at all.  It might be preferable to compress all
> this information into a single string attribute, as we do with unit,
> ucd, utype, etc.  Perhaps something like "wcs", "system", "frame",
 
I was initially going in this direction and it is roughly in line with the 
library of standard coordinate systems (I think in the appendix of the STC 
document), where one has things like ICRS-TOPO. That would simply this alot, 
and we could get rid of "flavor". For now, I just wanted to express what is 
needed, not necessarily the form it take. Otherwise: yes, this could easily 
be encoded in a single attribute and there are examples of that already in 
STC.

PS-flavor comes directly from STC :-)

-- 

Patrick Dowler
Tel/Tél: (250) 363-0044
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