standard units in eml

chad berkley berkley at nceas.ucsb.edu
Fri Sep 6 10:01:10 PDT 2002 

oh yeah.  I meant SI not ISO.  sorry for the confusion.

On Fri, 2002-09-06 at 08:24, Matt Jones wrote:
> Actually, the base units came from SI, not ISO.
> 
> We took our basic list from here:
>     http://physics.nist.gov/cuu/Units/
> 
> SI has a rigid prefix structure, so we tried to be consistent and 
> provide all of the prefixes in the range nano- to mega-, even if for 
> some base units some of the prefixes are rarley used.  The base list 
> included only the 7 SI units for the 7 SI base quantities, which are:
> 
> length  meter  m
> mass  kilogram        kg
> time  second  s
> electric current  ampere  A
> thermodynamic temperature        kelvin  K
> amount of substance  mole  mol
> luminous intensity  candela  cd
> 
> Every other unit can be derived from these, including energy and the 
> others you mentioned.  According to SI, mole is a fundamental unit.  We 
> then supplemented that list with derived types that we thought were 
> common, but I agree we need to add to it.  In particular, there's a list 
> of named SI units that are derived that could be added as well (see 
> Table 2 and Table 3 at http://physics.nist.gov/cuu/Units/units.html). 
> It would probably be good to add all of these.  The list would then be 
> quite long, especially if all of the prefixes are included in the 
> nano-mega range, but its probably worth it.
> 
> Matt
> 
> chad berkley wrote:
> > 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
> >>>*******************************************************************
> >>>
> >>>_______________________________________________
> >>>eml-dev mailing list
> >>>eml-dev at ecoinformatics.org
> >>>http://www.ecoinformatics.org/mailman/listinfo/eml-dev
> >>
> >>-- 
> >>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
> >>_______________________________________________
> >>eml-dev mailing list
> >>eml-dev at ecoinformatics.org
> >>http://www.ecoinformatics.org/mailman/listinfo/eml-dev
> > 
> > 
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> 
> 
> 
> -- 
> *******************************************************************
> 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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