Explainations of interface/serializations (what is required) (Was: Re: [QUANTITY] Data Model for Quantity v0.5

[Pierre Didelon]

Brian Thomas wrote:

> 	Hi Pierre,
> 
> On Monday 10 May 2004 12:11 pm, Pierre Didelon wrote:
> 
>>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
>>
...
>>  	Finally, at which level is the accuracy related?
> 
> 
> 	As I said above, the BQ should allow accuracy.
Beurk! Why?
If some people want accuracy let them use CoreQ,
and let people who don't need accuracy use BasicQ.
But OK, as you show below accuracy is optionnal so...
up to DM-Quantity core group decision.



>>So I must admit that I am completly confused, some clarification is needed,
>>at least for me.
> 
> 
> 	I'm happy to try to help.
> 
thanks
> 
>>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)
> 
> 
> 	This *is* in the document, but may not be clear. 
Where, which page. Looking for same info regarding Frame
and I didn't succeed. Apologies.
OK, I will take a stab at
> 	a summary:
> 
>          Basic Quantity [id attribute optional]
>                  UCD  -   Optional
>                  CoordSystem - Optional
>                  Units - Optional (Defaults to "unitless")
>                  DataType - Optional (Defaults to "string of arbitrary length")
>                  Value - Required
>                  Accuracy - Optional

so the minimum Quantity can have only a value (even without UCD),
with additional info "from" frame; name and description (required or optional?)
>  
>          Core Quantity [id, size attributes optional]
>                  UCD - Optional
>                  CoordSystem - Optional
>                  Units - Required (But if absent in serialization it defaults to "unitless")
>                  DataType - Required (But if absent in serialization it defaults to "string of arbitrary length")
>                  Values - Required
>                  Accuracy - Optional
> 
>          Std Quantity [id, size attributes optional]
>                  UCD - Optional
>                  CoordSystem - Optional
>                  Units - Required (But if absent in serialization it defaults to "unitless")
>                  DataType - Required (But if absent in serialization it defaults to "string of arbitrary length")
>                  AxesList (gives coordinate frames for accessing values in Q) - Optional
>                  Values - Required
>                  AltValues - Optional
>                  Accuracy - Optional
> 
> 
>    	So you can see that "dataType", "units" and "values" are required at all
> 	levels. 
So make it more clear by stabbing it with :
Required (But if absent in serialization it defaults to "unitless")
even for BasicQ, isn't it better?
What is the diff. defining interfaces?
But for the first 2 types of information, we allow for sensible defaults,
> 	in order that the serialization can be made more compact and to promote 
> 	use of Q interface in the widest variety of XML nodes.
> 
> 
> 
> 
>>Attempting to clarify my mind on basicQuantity first... at least.
>>Does it make any sense?
> 
> 
> 	Did that explanation help?
> 
yes, at least for my understanding,
but may be not completly for agreement yet ;-)
thanks.

> 	Regards,
> 
> 	=b.t.
> 
> 

-- 
Pierre 
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