Coordinates model - Working draft.

[CresitelloDittmar, Mark]

Markus,

I haven't taken the time to digest this fully, but this paragraph struck me.
You seem to be conflating the model and its annotation too directly.
The model is not repeating serialization information, but representing the
concepts.
A physical quantity has these concepts
  * it is continuous, or integral (datatype)
  * it has units
  * it has a value.
These are serialized in VOTable as a PARAM
The PARAM is annotated as a Quantity type.

I agree that it is important to know what the effect on serialization is..
that is why we have example files which clearly show these elements.
But the model is not tied to any serialization format.  The fact that
VOTable has a param which includes value, unit and type, does not mean
that the model should not also have something with those features.  It
means that at this fine-grain level, they align (which they should).

Also, the model is showing the type of the concept (eg RealQuantity has a
floating point value, so is continuous).  This is true whether the VOTable
has the value serialized as a float (10.0), integer (10) or string ("10").
Any should be valid so long as it can be translated to a RealQuantity.

Mark

PS: the scope and requirements for the model are listed in the document.

On Tue, Jan 15, 2019 at 9:38 AM Markus Demleitner <
msdemlei at ari.uni-heidelberg.de> wrote:

>
> Anyway, to get this away from abstract speculation: Are there actual
> use cases that would profit from repeating type/unit/value
> serialisation in the data model?  If so, perhaps there are better,
> more layer-respecting solutions for them?
>
>
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