Re: [Data Cubes] unit of measure with multiple measures

Hi Thomas,

On 18/07/12 17:30, Thomas Bandholtz wrote:
> Hi,
>
> i am dealing with multiple measures and i want to give them individual uoms.
> http://www.w3.org/TR/vocab-data-cube/ is a little bit vague about this.
>
> I read: "Specifically in this example we can use the predefined
> sdmx-attribute:unitMeasure which in turn corresponds to the COG concept
> of UNIT_MEASURE."
>
> and later:
>
> "Attributes can also be attached directly to the qb:MeasureProperty
> itself (e.g. to indicate the unit of measure for that measure) "

Indeed you can attach sdmx-attribute:unitMeasure to the 
qb:MeasureProperty (if you declare that as the attachment level) or to 
the observation (if you use the measure dimension approach to 
multi-measure cubes).

> I want to provide a qb:codeList with a set of uoms, but the schema says
> i can do this only with a qb:DimensionProperty, why?

No, it's the other way round.

The schema requires qb:DimensionProperty to be coded (and that's one of 
the restrictions under review in GLD) but it is doesn't prevent other 
uses of CodedProperty.

qb:ComponentProperty > qb:CodedProperty > qb:DimensionProperty
                      > qb:AttributeProperty
                      > qb:MeasureProperty

There's no disjointness assertions between qb:CodedProperty and the 
others. Something can't be both a qb:DimensionPropety and  a 
qb:AttributeProperty but it can be both a qb:CodedProperty and 
qb:AttributeProperty.

So if you have a qb:AttributeProperty you want to want to use to declare 
the UoM and you want to declare those as skos:Concepts then you can 
indeed use qb:codeList to associate the skos:ConceptScheme for the UoMs 
with the qb:AttributeProperty.

However, for declaring units of measure you might want to consider using 
an existing vocabulary. In particular we've found QUDT [1][2] very 
useful and adds more value than a simple concept scheme.

Dave

[1] http://www.qudt.org/
[2] http://www.linkedmodel.org/catalog/qudt/1.1/index.html

Received on Thursday, 19 July 2012 08:15:59 UTC