it is a pretty weird unit, since it is partway between 2-d and 3-d space, and therefore partway between the concept of 'area' and that of 'volume'. So whether it is acceptable depends on whether we think that such concepts are meaningful in the activity we call 'measurement' in the physical world. Probably there are weird units like this in quantum mechanics, or other esoteric mathematical spaces, so then it comes down to scope of UCUM - presumably not all of science, just physical measurement?
Changing openEHR or HL7 to handle it probably would not be hard, but it might open up a can of worms, and also just plain annoyances, by allowing fractional dimensions (i.e. as soon as you start using floating point numbers for values that are almost always integers, computers struggle to get it right...). - thomas On 29/04/2011 01:48, Grahame Grieve wrote: > Hi Leo > > Gunther says that these units are not proper units. > > http://www.xkaw.com/Education_Reference/Science_Mathematics.asp?id=2276318 > > There's a possible question of scope alignment here. It's kind of tantamount > to > saying that a measure like that is not a proper measurement. I don't think > I agree with that. > > To pursue the UCUM issue, you need to make at ticket at > http://www.unitsofmeasure.org/ > > I think that there's a tension here between the notion of purity from UCUMs > point of view, and the use of UCUM in the measurement data types (PQ in > HL7 v3 and DV_QUANTITY in openEHR - both have the same scope and the > same usage of UCUM) > > Also see http://www.unitsofmeasure.org/wiki/ProcedureDefinedUnits > > Grahame > > * * -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openehr.org/mailman/private/openehr-technical_lists.openehr.org/attachments/20110429/9213f009/attachment.html>
