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MMI Marine Device Ontology
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reference scale #5

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago 
(from 2010-04-27 telecon minutes,
http://marinemetadata.org/community/teams/ontdevices/mtgs/am20100427)

Description of the action item
Where do scale references fit in the ontology? I'm unclear whether it is
better linked to unit of measure, the sensor or calibration? For example,
http://www.seawatersolutions.com/practical-salinity-scale-pss78-3-w.asp.
Note that codes from BODC embed some of these standards in their
definitions. Probably not the best way, since difficult to extract and
facilitate automatic conversions....

(John and Reyna to follow up on this.)

Please provide any relevant information/links below

Original issue reported on code.google.com by caru...@gmail.com on 18 May 2010 at 2:49

GoogleCodeExporter commented 9 years ago 
 Most standards for specifying values require units but not reference scale.  I think it's probably a deep ontological question whether the reference scale is more of a process associated with the measurement, or a narrower characterization of units. Depending on the purpose of the ontology, I could see it either way.  It also will depend on implementations you're dealing with -- some systems may consider units invariant and consider the reference scale part of the process, whereas others (like SSDS) may consider the reference scale either an entity in its own right, or linked to the units in some way.

Correct that embedding the scale in the definition of a *measurement* is not so 
good, though embedding it in the definition of the units could be good, if your 
intent is to pin down the units that carefully.

I know where the absolute answer to this can be found.  The OOR folks had a 
project on Units of Measure. If they did not come to a conclusion, I don't know 
who would.  It may even be in their ontology.

In pH, the units terms actually incorporate what might otherwise be called the 
reference scale.

If that isn't satisfying, my own answer is that units have reference scales, 
and these may be modeled either as part of the units (as in pH), so the units 
term will change if the reference scale changes; or as a relationship, wherein 
the reference scale is associated with a particular unit.

Original comment by jgrayb...@ucsd.edu on 22 Jun 2010 at 7:04

GoogleCodeExporter commented 9 years ago 
So this issue seems to be actually closely related with units of measure. 
http://www.qudt.org/ looks like a very relevant pointer in this case. In the 
QUDT ontology, "A system of units is a set of units which are chosen as the 
reference scales for some set of quantity kinds together with the definitions 
of each unit."  

I will be looking more closely into this ontology later on, but in the meantime 
I will also be attentive to further comments on this issue.

Original comment by caru...@gmail.com on 22 Jun 2010 at 7:22