standard units in eml

[chad berkley]

Hey Tim,

We took a lot of that directly from ISO.  STMML allows derived types to
be defined, so basically, we just need a list of units to define.  That
list was pretty much off the top of Matt's and my head (and from looking
at ISO for the base types).  Units are a very complicated issue.  We
just need some good brain storming to come up with a decent list of
ecologically relevant units.  Keep in mind that STMML is extensible too
so even if a unit is not listed in the unit dictionary, it can still be
defined and used.  Check out http://www.xml-cml.org/stmml/ for more
info.

chad

On Fri, 2002-09-06 at 07:51, Tim Bergsma wrote:
> Regarding units...
> 
> I see several listed in eml-attribute that I've never seen used
> anywhere, such as centisecond and hectosecond.
> 
> There should be at least a base type for all the irreducible physical
> measurements.  I see length, mass, time, temperature, BUT NOT energy
> (joule, calorie; okay, its really a derived type, for you purists) force
> (e.g. newton) or magnetism (tesla).  (Hey, migratory birds respond to
> magnetic fields, don't they?) 
> 
> Candidates in the common but derived category are area (square meter)
> speed (meter per second, e.g. streamflow) pressure (kiloPascal)
> electrical charge (coulomb) power (watt) electrical potential (volt)
> electrical resistance (ohm) and radioactivity (suggestions anyone?  for
> ecological research near nuke plants).  The electrical stuff may seem
> arcane, but electrical conductivity of stream water is a common
> ecological measurement, and is defined in terms of electrical resistance
> and length (e.g. megohm*cm).
> 
> Just for fun, I'll argue that mole is not a unit.  It's just a number. 
> You can as easily have a mole of photons (6.023 * 10^23 photons = 1
> Einstein) as a mole of carbon12 atoms (= 1 gram).  Where unqualified, I
> guess mole of molecules is implied.
> 
> Tim.
> 
> Matt Jones wrote:
> > 
> > Just a quick reminder -- we have a standard list of units in eml defined
> > in the STMML language, and part of the "unitDictionary" simpleType in
> > eml-attribute.xsd.  These are the SI units plus a few additional
> > commonly used non-si things.  it would be useful if you reviewed the
> > list and suggested any additions or changes before the RC1 release.
> > Today would be good so we can incorporate feedback into RC1!  Thanks.
> > 
> > Matt
> > --
> > *******************************************************************
> > Matt Jones                                    jones at nceas.ucsb.edu
> > http://www.nceas.ucsb.edu/    Fax: 425-920-2439   Ph: 907-789-0496
> > National Center for Ecological Analysis and Synthesis (NCEAS)
> > 
> > Interested in ecological informatics? http://www.ecoinformatics.org
> > *******************************************************************
> > 
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> 
> -- 
> Tim Bergsma
> LTER Information Manager
> W.K. Kellogg Biological Station
> Michigan State University
> Hickory Corners, MI   49060
> 616/671-2337
> tbergsma at kbs.msu.edu
> http://lter.kbs.msu.edu
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