February 25, 2011
Days in month
Linking an interesting discussion into whether a unite (e.g., meters) should be associated with a variable that is a count. For example, does a variable such as Number of Days in Month receive a unit of "days"?
The exchange is between a few ecological data types. I'll cite a few snippets here.
> This question is drifting out of the datetime issue and into the count > issue which I don't think we ever resolved very well. To my > recollection, counts (and percents, etc) were not considered > measurements by STMML and are all dimensionless units. I don't think we > are going to start naming units for all the things we might count > integer numbers of, are we? I would have encoded day of the year as > simply ratio with a unit of dimensionless and a domain of 0 to 365.
We put 'nominalDay' into EML as a 'day' unit of constant length just to accomodate those people that wanted to refer to time durations without reference to a calendar and all of its associated problems. Thus, a nominal day is a unit of time that is exactly 60*60*24 seconds.