content, format, ctype, or xtype ?

[Paul Harrison]

On 2009-05 -13, at 19:24, Patrick Dowler wrote:

> So.... UCD?
>
> It looks like I object to everything but ucd: it allows one to say  
> "this is a time". Maybe restriction is enough:
>
> MJD: DOUBLE <-> datatype="double" ucd="time"
> ISO8601: TIMESTAMP <-> datatype="char" ucd="time"
> STC-S: REGION or POINT <-> datatype="char" ucd="pos" ?
>
> Specifically for upload to a TAP service, if the ucd attribute was  
> missing, the service would put the timstamp values into a VARCHAR  
> column instead of a TIMESTAMP column. Some things might still work.  
> If someone replies that there is a suitable UCD fragment for  
> position (pos?) and energy (?) then maybe we just have to spell this  
> out (specifically, the table in TAP 0.42, page 19 would be changed  
> from VOTable:format to VOTable:ucd and we would specify UCD  
> fragments that signify the content).
>
> PS-when I say ucd="time" I really mean the ucd attribute contains a  
> "time" fragment. Can we make this precise enough?
>



I don't think that this covers all the bases, as there is also the POS  
expressed as sexagesimal - but running with this idea, what about a  
set of secondary UCD words format.MJD, format. ISO8601, format.STC,  
format.hms, format.dms to be added to time.epoch etc.


Paul
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