stmml units: dimensionless and undefined

[Scott Chapal]

Tim Bergsma <tbergsma at kbs.msu.edu> writes:

> After posting the question, I found an excellent use for both!  Some
> attributes really are dimensionless, such as nominal attributes. 
> Preserving 'undefined' (as a placeholder) allows system developers to
> make 'Units' required, even if all attributes have not yet been
> categorized.  I would argue, however, that dimensionless and undefined
> should have different descriptions.

 Dimensionless \Di*men"sion*less\, a.
     Without dimensions; having no appreciable or noteworthy
     extent. --Milton.

  undefined
       adj : not precisely limited, determined, or distinguished; "an
             undefined term"; "undefined authority"; "some undefined
             sense of excitement"; "vague feelings of sadness"; "a
             vague uneasiness" [syn: vague] [ant: defined]
  __________________________________________________________________

It seems that dimensionless is a more determinate term in the intended
usage in EML -- to convey the absence of an associated unit.

  <unit id="undefined" name="undefined" unitType="undefined">
    <description>Unit for fields with undefined (unknown) unit</description>
  </unit>

  <unit id="dimensionless" name="dimensionless" unitType="undefined">
    <description>Unit for fields with no unit -- "dimensionless"</description>
  </unit>

Is that intention better stated using the term "unitless" or "noUnit"?

  <unit id="undefined" name="undefined" unitType="undefined">
    <description>Unit designation for fields with undefined
                 (or unknown) unit</description>
  </unit>

  <unit id="noUnit" name="noUnit" unitType="undefined">
    <description>Unit designation for fields that have no unit</description>
  </unit>

-Scott

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Scott E. Chapal_________________________________________________
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