concept representation/displaying language?

[Roy Williams]

Carlos Rodrigo Blanco wrote:
> In that way, somebody can download the simple votable and, if he is 
> interested in displaying, he can download the xfd document and do the 
> matching. 

Perhaps the key observation here is that if you have one of these 
special VOTables (with T_{eff} etc), then you will have many of them. 
Instead of putting all the semantics and presentation and meaning into 
each VOTable instance, you have put them into a separate document -- 
data model, schema, stylesheet, whatever you want to call it.

The VOEvent syntax is similar in many ways to VOTable. We recognized 
that events do not come singly, but in a stream of similarly structured 
events. Therefore we built the VOEventStream object to hold the 
information common to these. The stream is the metadata that goes in the 
registry. See for example http://www.skyalert.org/streams/, and click on 
"Detail" for any of the listed streams.

Similarly, we could build and register your "xfd" definitions, that 
define community-specific, or application-specific subclasses of VOTable.

Roy


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California Institute of Technology
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