A modest proposal for VOEvent

[Rob Seaman]

Hi Roy,

>>> Here's a very good role for a simple VOEvent vocabulary:
>>>
>>>    <Param name="q" type="voe:massRatio" ...> ...
>>>    <Param name="e" type="voe:orbitalEccentricity" ...> ...
>>>    <Param name="i" type="voe:orbitalInclination" ...> ...
>
> I believe that the existing standard covers semantic tagging very  
> well, without any compelling need for change. I do not see that  
> type="voe:orbitalEccentricity" carries any more semantic information  
> than ucd="src.orbital.eccentricity", which we have already agreed is  
> the preferred semantic mechanism of VOEvent.

Um, I was attempting to encourage Rick to document a draft of the  
VOEvent vocabulary.  How it gets expressed in a packet is a question  
for the WG.  It might not be a type attribute, but certainly could be  
the value.  Group two Params and you can do exactly what Rick is  
suggesting, if a bit more pedantically.

We never stated that UCDs were the beginning and end of our semantic  
escapades - else, why the vocabulary effort at all?

>>> P.S. Does the current schema allow <Param>value</Param> or must  
>>> one use attributes?  Wouldn't this be a good change?
>
> No it is NOT a good change! I have written thousands of lines of  
> code around the existing standard for the Param element, so I can  
> see a big cost for me at least if this change happens.
>
> Please don't make arbitrary changes. VOEvent is complex enough  
> already!

Nobody is going to make arbitrary changes.  The standard is the  
responsibility of the entire WG.  The wording is:

	"a Param must be expressed as an empty element"

(http://www.ivoa.net/Documents/REC/VOE/VOEvent-20061101.html#toc-header-16 
)

I don't remember why folks wanted it this way - is this required by  
VOTable?  Or perhaps to restrict an overly flexible VOTable phraseology?

On the other hand, some folks want to add a datatype.  Why not  
consider other changes before limiting the options again?   
Brainstorming should proceed in an open enough forum that every  
possibility receives a hearing.  Hearing is not the same as instant  
adoption.

Rob