standard units in eml

[Matt Jones]

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
*******************************************************************