VOEvent References

[Frederic V. Hessman]

Dear Norman et al.,

On second thought, put back the corks.....

> On reflection, I think that @sciencetype (for the meaning of the  
> information) and @mimetype (for the format) might be better  
> attribute names.

The "mimetype" designation has the great beauty of being simple and  
compliant with the rest of the world, but I imagine that there might  
be cases where non-standard content may need to be shipped.    
"sciencetype" also sounds ok, but maybe we can do even better.  I  
remember the initial discussion at CalTech when we came up with  
<What>, <WhereWhen>, <Why> and how wonderful it was to simply say what  
one means.  If the "type" attribute is supposed to say what the format  
of the dataq are in and the semantic content of the reference is  
supposed to say what the reference "means", then may I suggest we  
considering the following brainstorming examples which will NOT work  
with MIME:

	<Reference format="vo://net.ivoa/vospace/core#sextractor"   
meaning="ivoat:catalogues" />
	<Reference format="http://gsfc.nasa.gov/rdf/ 
swift#SwiftByteFormatStream"  meaning="ivoat:telemetry" />
	<Reference format="skypublishing:web2/ 
skos#CelestiaObjectDescriptionFile"  meaning="ivoat:simulation" />
	<Reference  
format 
= 
"noao:lsst 
#moredatathanyoucanpossiblyprocessbuthereitisifyouthinkyoucandosomethingwithit 
" meaning="ivoat:survey" />

Better to have a general-purpose means of expressing any kind of  
format (which is also just a vocabulary) and a basic set of examples  
pre-defined by the IVOA for convenience use by those less-inclined to  
invent their own.

Thus, in the true VOEvent tradition of "make it simple" and "say what  
you mean", I vote for

	<Reference format="format-vocabulary-term" meaning="semantic- 
vocabulary-term">Put your ignored text here.</Reference>

Basta.

Rick

P.S. Oh yes, one IS allowed to include several <Reference>'s anywhere  
one needs them, isn't one.....?  E.g. finder chart reference plus  
light curve reference.  I still don't like having just one semantic  
meaning (how do I say "spectrum of a galaxy"?), but don't want to open  
that can of attribute versus child-tag worms.