A question re: using XML validation for ensuring proper units usedin instance document

Greetings,

My group at Pitney Bowes is investigating how
best to use unitsML for descriptions of mail items. We are building an XML
schema that represents the physical dimensions of a mail item, including width,
height, thickness, weight, etc. One of the things we want the schema to ensure
is that those who use the schema use one of a set of proper units for a given
dimension, e.g., length dimensions can be in, cm, m, yd but not lb or oz. 

 

Our approach for this is to create our own
units "database," i.e., an instance document that conforms to unitsML
that uses a pattern for the identifiers of the units. This way, we can use
standard XML validation for ensuring that appropriate units are used. For
example, the identifier for a specified inch unit is "distance-in"
and one for a cm unit is "distance-cm." We create specialized
measurement types that restrict the identifiers used in a unit attributes to
the pattern. This approach means, as far as we can tell, that we will need to
always have our own "database." 

 

Question: is there a better way in unitsML
where we can use the XML validation feature to ensure that the proper units
(i.e., one from a set) are used for a given quantity? If not, is there a way
that we could have a "sameAs" description (URL/IRI and units
identifier) in the UnitType (e.g.) where we could connect our description of a
unit to your standard description of a unit, and so enable applications to leverage
information, like conversions, etc, that look to be a part of a bigger and more
complete database?

 

Thanks,

Deborra Zukowski

Pitney
Bowes