Expressing 2- and 3-D coordinates

[Arnold Rots]

I met with Jonathan who is back from vacation today, and we decided to
go with a somewhat modified option b:

   STC for the time being converts to enumerating the vector
   components as in my first message, and may change back to list
   types when list support is firmly there.

The STC schemata will be adapted accordingly.

  - Arnold


Arnold Rots wrote:
> Let me try to draw some conclusions from the discussion, so far.
> But one comment to preface that: I'd be very hesitant to encourage
> multiple STC-based schemata; that also was the main rationale for
> rejecting STCLite.
> 
> 
> VO schemata ultimately will need to support list types since arrays
> are such an integral part of our data.  In that context and
> considering that such a list type is the more natural way to express
> coordinate vectors (though I realize that this is my subjective
> judgment) the present use of lists of doubles for coordinate vectors
> would be preferable.
> 
> Ed promises us that list will be supported in XPath2, that it will
> become reality by the end of February, that parsers will incorporate
> the support soon after that, and that support is currently available
> through extensions.
> In summary: it can be handled now with a little bit of extra effort
> and in three months it will not be an issue anymore.
> 
> So, we are left with two questions:
> 
> 1. Can the VOEvent community live with the extra effort for three
>    months?
> 
> 2. Is Ed's prognosis accurate?
> 
> (Though not necessarily in that order)
> 
> If the answer to the first question (potentially amended by the answer
> to the second one) is affirmative, we'll stick with what we have,
> aside from the already planned modifications that had been agreed to
> before.
> If the answer is no, we have three options:
> 
> a. STC sticks with list types and VOEvent may do something else.
> 
> b. STC temporarily converts to enumerating the vector components as in
>    my first message, and changes back to list types when list support
>    is firmly there.
> 
> c. STC converts permanently to separate the components witin the
>    vector element.
> 
> Comments?
> 
>   - Arnold
> 
> 
> 
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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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