EML

The following exellent email from Don Henshaw addresses a large number of
missing or problematic units in the unit dictionary. We need to 1) fix these
and others that are identified, and 2) figure out how to release new versions of
the eml-unitdictionary without releasing new versions of EML.

---------------- Message from Don Henshaw ---------------------
David,
I have reviewed the Andrews unit dictionary. The following are units of
measurement that we have used at the Andrews that I did not find in
eml-2.0.0\eml-unitDictionary.xml, as well as a few other notes.

Thanks,
don

pressure: hectopascal (=100 pascals)
volume: cubic centimeters
volumetricArea: cubic meters per hectare
volumetricArea: cubic meters per square meter
massDensity: megagrams per cubic meter
arealMassDensity: grams per square centimeter
arealMassDensity: megagrams per hectare
arealMassDensityRate: grams per square meter per day
amountOfSubstanceWeight: micromoles per gram
amountOfSubstanceWeightFlux: micromoles per gram per day
amountOfSubstanceWeightFlux: micromoles per gram per hour
amountOfSubstanceWeightFlux: nanomoles per gram per day
amountOfSubstanceWeightFlux: nanomoles per gram per hour
speed: inches per hour (used more as a rate than a speed)
energy?: megajoule per square meter per day (solar radiation)
energy?: langley (1 langley=4.187joules per square centimeter, 41870 joules per
square meter)
energy?: langleys per day (solar radiation)
conductance?: micro mhos per centimeter

I do not think there are unit types for the following (I assigned unit type names):
massPerMassRate: micrograms per gram per day
massPerMassRate: micrograms per gram per hour
massPerMassRate: micrograms per gram per week
massPerMassRate: nanograms per gram per hour
areaPerArea: square meters per hectare
luminanceRate??: micromoles per square meter per second (light measurement from
LICOR instrument)

Not sure how these fit:
milliequivalents per 100 grams
pH units
ppm (parts per million)
ppb (parts per billion)

What about the following use of degrees, minutes, seconds?
degrees azimuth
decimal degrees of latitude or longitude
degrees, minutes, seconds of latitude, longitude

On another topic:
Can a julian date be represented in the format string for measurementScale of
datetime i.e., YYYYddd

Other notes (being rather picky): pertaining to eml-unitDictionary.xml (2.0.0)
following units seems to show wrong abbreviation and multiplier
milliGramsPerMilliLiter
cubicMicrometersPerGram

The following unit names seem contrary to the convention of showing units in
singular form:
squareCentimeters
squareMillimeters
squareKilometers
cubicMeterPerKilogram

Not all units show an abbreviation, even when an obvious one exists, ie., kg/ha
or g/g liter shows "L" as the abbreviation