[QUANTITY] Data Model for Quantity v0.5

[Pierre Didelon]

Brian Thomas wrote:


The serialization document lays out the
> 	structure, which is fairly simple. Here's a copy :
> 
> --- begin snippet ----
> 
>    The components of these types of quantity are given elsewhere, but
>    summarized here, are:
> 
>         Basic Quantity
>                 UCD
>                 CoordSystem
>                 Units
>                 DataType
>                 Value
>                 Accuracy
> 
in DM for Quantity V0.2 document  p13. diag show accuracy linked to core Quantity
but BasicQuantity interface on p.14 give methods to handle accuracy...
so even doc is contradictory.
XSD files and corresponding schema/diag seems to integrate accuracy at the basic level.
Finally, at which level is the accuracy related?
Moreover in § 7.6 examples are not clear; they use <quantity> without always
precising basic/core/standard case, at least in part 1. & 3.
Is this intentionnal to illustrate the polymorphism of the quantity inheritance?
Any way it is misleading and not precise enough, at least for example/illustration clarity.
If 7.6.1 illustrates basicQuantity serialization, then altValues tag seems
not appropriate here, as it is relevant only for standardQuantity (p13 diag)?

So I must admit that I am completly confused, some clarification is needed,
at least for me.
Moreover it would be nice to have a clear statement
of which parts are mandatory and which ones are optionnal, at each level,
in clear english (understable by non-english mother spoker like me)
outside xsd doc. But then it is more related to data-modelling or serialization
than to class interface, would you say. Yes... but you can then define methods
which are allowed to return null values and others who are not.

Attempting to clarify my mind on basicQuantity first... at least.
Does it make any sense?
SY,
PiD
>         Core Quantity
>                 UCD
>                 CoordSystem
>                 Units
>                 DataType
>                 Values
>                 AltValues
>                 Accuracy
> 
>         Std Quantity
>                 UCD
>                 CoordSystem
>                 Units
>                 DataType
>                 AxesList (gives coordinate frames for accessing values in Q)
>                 Values
>                 AltValues
>                 Accuracy
> 
> --- end snippet ----
> 
> 
...
> 
> 	=b.t.
> 

-- 
Pierre 
--------------------------------------------------------------------------
DIDELON :@: pdidelon_at_cea.fr        Phone : 33 (0)1 69 08 58 89
CEA SACLAY - Service d'Astrophysique  91191 Gif-Sur-Yvette Cedex
--------------------------------------------------------------------------