Found something that should go in unit dictionary (I think)

[Peter McCartney]

Agreed - in this case "cells" could be identified as the domain, perhaps. It
would be nice if we could find a way to make the dictionary more extensible
without having to start from scratch each time we want to make a ratio or a
density against an already defined unit.....

We have a similar problem with proportions which are similar to densities
except they are against an arbitrary number that represents a "whole". I
think we left off last week deciding to also treat counts and proportions as
ratio scale and use some sort of unit (dimensionless?). Is that right? it
seems like we need some more unambiguous identification of counts and
proportions comparable to what we have for densities (we have a unit type
defintion for density,but not for counts or proportions.

Peter McCartney (peter.mccartney at asu.edu)
Center for Environmental Studies
Arizona State University
480-965-6791 

> -----Original Message-----
> From: Chad Berkley [mailto:berkley at nceas.ucsb.edu]
> Sent: Wednesday, November 13, 2002 9:01 AM
> To: Dan Higgins
> Cc: David Blankman; Chad Berkley; Tim Bergsma; Eml-Dev (E-mail)
> Subject: Re: Found something that should go in unit 
> dictionary (I think)
> 
> 
> Hi David and Dan,
> 
> Dan, you're right.  There is already a unitType called 
> volumetricDensity which 
> is essentially a numberPerVolume.  Unfortuneately, there is no unit 
> numberPerMilliliter, only numberPerMeterCubed.  So David, we 
> can add the unit 
> numberPerMilliliter but like Dan said, it would be impractical to add 
> XPerMilliter where X could be anything.  We should probably 
> add number per 
> Milli, micro, ...,kiloliter while we're at it.
> 
> chad
> 
> Chad Berkley
> Metadata Systems Developer
> National Center for Ecological Analysis and Synthesis
> 735 State St. Suite 300
> Santa Barbara, CA 93117
> 
> 
> Quoting Dan Higgins <higgins at nceas.ucsb.edu>:
> 
> > Hi David,
> >     Isn't the unit here really 'number per milliliter' rather that 
> > 'cells per milliliter'. (i.e. just a number density) Cells 
> is the thing 
> > being counted. Otherwise, one would have units of 'tadpoles 
> per liter', 
> > 'apples per square mile', 'oranges per acre'. etc with a 
> different unit 
> > for every possible thing that one might want to count.
> > 
> > Dan Higgins
> > 
> > ---
> > 
> > David Blankman wrote:
> > 
> > > Chad and Tim,
> > >
> > > I am starting to do EML conversions for the McMurdo LTER. 
> They have a 
> > > number of data tables  that relate to plankton. The unit 
> that they use 
> > > is cells/milliliter. I am guessing that this is a unit 
> that others 
> > > might use.
> > >
> > > David
> > >
> > 
> > 
> > 
> 
> 
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