[QUANTITY] Data types question (Was: Re: [QUANTITY] The discussion so far

[Gerard Lemson]

Hi Brian
My answer must be seen against a question I pose in my reply to Jonathan.
I would really like to get feedback to this one:

which concept(ion) of Quantity are we really trying to model in the
"Quantity modeling effort" ?

At ADASS we seemed to agree somewhat that your and our models diferred along
the lines that
your model seems to model physical/persistent/stored representations of
(collections of) numbers.
Ours is a conceptual model indicating what other (meta-)data/information is
required to make
scientific sense of these numbers.
If Jonathan's suggestion is that it is harder to describe and implement a
storage model for
complex types I might agree. To describe a conceptual Quantity correctly
using a complex type is
less of a problem though, we've already done it. But even in the former case
it seems that we
better very quickly learn how to deal with types complexer than a single
number, seeing the
request/proposal for grouping in VOTables (and even UCDs) for example.
Gerard

--
* Gerard Lemson                       * Tel: +49 (0)89 30000-3316
*
* MPI fuer extraterrestische Physik   * Fax: +49 (0)89 30000-3569
*
* Giessenbachstrasse                  *
*
* Postfach 1312                       *
*
* D-85741 Garching, GERMANY           * email: gerard.lemson at mpe.mpg.de
*


> -----Original Message-----
> From: Brian Thomas [mailto:brian.thomas at gsfc.nasa.gov]
> Sent: Friday, October 31, 2003 4:02 PM
> To: Gerard Lemson; dm at ivoa.net
> Subject: [QUANTITY] Data types question (Was: Re: [QUANTITY] The
> discussion so far
>
>
> On Friday 31 October 2003 08:34 am, Gerard Lemson wrote:
> > > Does Q support complex types?
> > >  Dowler::Type = Ellipse2D, Oct 27
> > >  Dowler, polygon types (Oct 29)
> > >  McDowell: suggest we not rule this out, but an initial implementation
> > >    would only support basic datatypes.
> >
> > I think we have to immediately, for example Position.
>
> 	Gerard,
>
> 	Well, I think the gist of Jonathan's comment is that we create a
> 	basic interface. This won't preclude trying to come up with more
> 	complex objects by some, but the focus for "blessed" types will
> 	be the basic ones. I agree with you that we need to "test" the
> 	interface with interesting types like Position. I agree
> with Jonathan
> 	that the intial focus are the "primatives" (but I bet thats pretty
> 	easy to knock off).
>
> 	Regards,
>
> 	-b.t.
>
>
> --
>
>   * Dr. Brian Thomas
>
>   * Code 630.1
>   * Goddard Space Flight Center NASA
>
>   *   fax: (301) 286-1775
>   * phone: (301) 286-6128
>
>
>