Standard Units for EML 2.2.0

Table includes name (also ID) for units that have been predefined in the EML 2.2.0 schema. These units can be used in the EML "standardUnit" field. Units not listed here should be described as EML "customUnit". For more information, contact support@environmentaldatainitiative.org. Search this using your browser's "Find" function, typically CNTL-F (windows, linux) or CMD-F (mac).
Name (ID) Definition
dimensionless a designation asserting the absence of an associated unit
second SI unit of time
meter SI unit of length
kilogram SI unit of mass
kelvin SI unit of temperature
coulomb SI unit of charge
ampere SI unit of electrical current
mole SI unit of substance amount
candela SI base unit of luminous intensity (luminous power per unti solid angle emitted by a point light source in a particular direction)
number a quantity or amount
nominalMinute one minute of time excluding leap seconds, 60 seconds
nominalHour one hour excluding leap seconds, 3600 seconds
nominalDay one day excluding leap seconds, 86400 seconds
nominalWeek one day excluding leap seconds, 604800 seconds
nominalYear one year excluding leap seconds and leap days, 31536000 seconds
nominalLeapYear one 366 day year excluding leap seconds, 31622400 seconds
nanogram 0.000000000001 kg
microgram 0.000000001 kg
milligram 0.000001 kg
centigram 0.00001 kg
decigram 0.0001 kg
gram 0.001 kg
dekagram .01 kg
hectogram .1 kg
megagram 1000 kg
tonne unit of mass equal to 1,000 kilograms, equivalent to approximately 2,204.6 pounds,1.102 short tons (US) or 0.984 long tons (imperial). Not part of the SI, but accepted for use with SI units and prefixes
pound 1 pound (symbol lb) in the Avoirdupois (commerce) scale, and defined as exactly 0.45359237 kg. Also equal to 16 avoirdupois ounces and to 7,000 grains.
ton standard US (short) ton = 2000 lbs
celsius A common unit of temperature
fahrenheit unit for temperature on the scale in which water freezes at 32 and boils at 212 under standard conditions.
nanometer .000000001 meters
micrometer .000001 meters
millimeter .001 meters
centimeter .01 meters
decimeter .1 meters
dekameter 10 meters
hectometer 100 meters
kilometer 1000 meters
megameter 1000000 meters
angstrom 1/10000000000 meter
inch unit of length in the (British) imperial and United States systems usually understood as 1/12 f a foot.
Foot_US 12 inches
foot 12 inches
Foot_Gold_Coast 12 inches
fathom 6 feet
nauticalMile defined as exactly 1,852 meters (6,076.1 ft; 1.1508 mi). Historically, defined as one minute of latitude.
yard 3 feet
Yard_Indian This is an ESRI unit and the multiplier comes from ESRI. It may not be accurate.
Link_Clarke This is an ESRI unit and the multiplier comes from ESRI. It may not be accurate.
mile 5280 ft or 1609.344 meters
nanosecond 1/1000000 of a second
microsecond 1/100000 of a second
millisecond 1/1000 of a second
centisecond 1/100 of a second
decisecond 1/10 of a second
dekasecond 10 seconds
hectosecond 100 seconds
kilosecond 1000 seconds
megasecond 1000000 seconds
minute 60 seconds
hour 3600 seconds
kiloliter 1 cubic meter
microliter 1/1000000 of a liter
milliliter 1/1000 of a liter
liter 1000 cm^3
gallon US liquid gallon
quart US liquid quart
bushel 1 bushel = 35.23907 liters
pint US liquid pint
meterCubed cubic meter
centimeterCubed cubic meter
inchCubed micromoles per square meter per second
radian 2 pi radians comprise a unit circle.
degree 360 degrees comprise a unit circle
grad a plane angle equivalent to 1/400 of a full circle
steradian standard unit of solid angle measure, it is the solid angle which cuts out an area on a sphere that is the square of the sphere's radius; as a ratio of two areas, it has no dimension
megahertz megahertz
kilohertz kilohertz
hertz derived unit of frequency in the SI, defined as one cycle per second
millihertz millihertz
newton newton
joule joule = N*m
calorie unit of energy: amount of energy to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere. cal = 4.1868 J
britishThermalUnit an energy unit: 1 btu = 1055.0559 J
footPound 1 ft-lbs = 1.355818 J
langley unit of energy density = 41840 joule/m^2, = 1 calorie/cm^2
lumen SI unit for the total quantity of visible light in a defined beam or angle. 1 lumen/m^2 = 1 lux. 1 lumen = 1 candela * steradian
lux SI derived unit for illuminance, or luminous flux per unit area. 1 lx = 1 lm/m^2 = 1 cd * sr/m^2
becquerel SI derived unit of radioactivity. the activity of a quantity of radioactive material in which one nucleus decays per second, and equivalent to an inverse second, s^-1.
gray SI derived unit of ionizing radiation, defined as the absorption of one joule of radiation energy per kilogram of matter (= 1 J/kg)
sievert SI derived unit of ionizing radiation dose (health effect of low levels of ionizing radiation on humans). 1 Sv = 100 rem (rem is an older, non-SI unit)
katal derived SI unit for quantifying enzymatic activity.A property of the catalyst (not rate of reaction), expressed in moles/second.
henry SI derived unit for inductance; in SI base units: kg * m^2 * s^-2 * A^-2
megawatt unit of power, to quantify rate of energy transfer. 1 W = J/s
kilowatt unit of power, to quantify rate of energy transfer. 1 W = J/s
watt unit of power, to quantify rate of energy transfer. 1 W = J/s
milliwatt unit of power, to quantify rate of energy transfer. 1 W = J/s
megavolt Derived unit for electric potential, electric potential difference, and electromotive force. 1 V = kg * m^2 * s^-3 * A^-1
kilovolt Derived unit for electric potential, electric potential difference, and electromotive force. 1 V = kg * m^2 * s^-3 * A^-1
volt Derived unit for electric potential, electric potential difference, and electromotive force. 1 V = kg * m^2 * s^-3 * A^-1
millivolt Derived unit for electric potential, electric potential difference, and electromotive force. 1 V = kg * m^2 * s^-3 * A^-1
farad SI derived unit of electrical capacitance, the ability of a body to store an electrical charge. 1 F = s^4 * A^2 *m^-2 * kg^-1
ohm an electrical resistance between two points of a conductor when a constant potential difference of one volt, applied to these points, produces in the conductor a current of one ampere
ohmMeter SI unit of electrical resistivity (fundamental property that quantifies how strongly a material opposes the flow of electric current). reciprocal of electrical conductivity.
siemensPerMeter SI unit for conductivity, measure of a material's ability to conduct an electric current.
siemensPerCentimeter SI unit for conductivity, measure of a material's ability to conduct an electric current.
siemens SI derived unit of electric conductance, susceptance and admittance (reciprocals of resistance, reactance, and impedance respectively). One siemens is equal to the reciprocal of one ohm (and also called "mho")
weber the SI unit of magnetic flux
tesla unit for flux density. 1 tesla = 1 Wb/m^2 (one weber per square meter).
pascal SI derived unit of pressure, 1 pascal = 1 newton/m^2
megapascal SI derived unit of pressure, 1 pascal = 1 newton/m^2
kilopascal SI derived unit of pressure, 1 pascal = 1 newton/m^2
hectopascal SI derived unit of pressure, 1 pascal = 1 newton/m^2
atmosphere unit of pressure defined as 101325 Pa (1.01325 bar), sometimes used as a reference or standard pressure
bar non-SI unit for pressure (deprecated in some fields). 1 bar = 100000 Pa
millibar non-SI unit for pressure (deprecated in some fields). 1 millibar = 1 hPa (100 Pa)
decibar non-SI unit for pressure. 1 decibar = .1 bar. Decibars are commonly used in aquatic environments because 1 db is approximately equal to depth in meters.
tonnePerHectare metric ton or tonne per hectare
gramPercentimeterSquared grams per square meter
gramPerMeterSquared grams per square meter
kilogramPerHectare kilograms per hectare
kilogramPerMeterSquared kilograms per square meter
milligramPerMeterSquared milligrams Per Square Meter
poundPerAcre avoirdupois pounds per acre
poundPerInchSquared avoirdupois pounds per square inch
gramPerCentimeterCubed grams per cubic centimeter
gramPerLiter grams per liter
gramPerMilliliter grams per milliliter
microgramPerLiter micrograms/liter
milligramPerLiter milligrams/liter
milligramPerMeterCubed milligrams Per Cubic Meter
kilogramPerMeterCubed kilograms per cubic meter
megagramPerMeterCubed megagrams per cubic meter
milligramPerMilliliter micromoles per square meter per second
milligramPerMeterCubedPerDay milligram per cubic meter per day
gramPerDayPerLiter grams Per (Liter Per Day)
footCubedPerSecond cubic feet per second
literPerSecond liters per second
meterCubedPerSecond cubic meters per second
are 100 square meters
hectare 1 hectare is 10^4 square meters
acre 1 acre = 4046.8564 square meters or 1 hectare = 2.4710 acres
centimeterSquared square centimeter
footSquared 12 inches squared
kilometerSquared square kilometer
meterSquared square meters
mileSquared 1 mile squared
millimeterSquared square millimeter
yardSquared 36 inches squared
bushelPerAcre bushels per acre, 1 bushel = 35.23907 liters/1 acre = 4046.8564 squareMeters
literPerHectare liters per hectare
literPerMeterSquared liters per square meter
meterCubedPerHectare meter cubed per hectare
meterCubedPerMeterSquared meter cubed per meter squared
meterSquaredPerHectare meter squared per hectare
meterSquaredPerKilogram square meters per kilogram
centimeterPerSecond centimeters per second
footPerDay feet per day
footPerHour feet per hour
footPerSecond feet per second
inchPerHour inches per hour
kilometerPerHour km/hr
knot unit of speed equal to one nautical mile per hour, exactly 1.852 km/hour
meterPerDay meters per day
meterPerSecond meters per second
milePerHour miles per hour
milePerMinute miles per minute
milePerSecond miles per second
millimeterPerDay millimeters per day
millimeterPerSecond millimeters per second
yardPerSecond yards per second
meterPerSecondSquared micromoles per square meter per second
inverseMeter reciprocal of meter, or 1/meters
inverseCentimeter also called reciprocal centimeter
meterCubedPerKilogram cubic meters per kilogram
micrometerCubedPerGram cubic micrometers per gram
amperePerMeterSquared amperes per square meter, unit of current density
amperePerMeter ampere per meter
molePerMeterCubed moles per cubic meter
molePerLiter moles per liter (perferred over molarity, as molarity refers only to dissolved substances)
millimolePerLiter millimoles per liter
micromolePerLiter micromoles per liter
nanomolePerLiter nanomoles per liter
millimolePerMeterCubed millimoles per cubic meter
microequivalentPerLiter concentration of charge (on dissolved ions). conversions must know the name of the ion; a single multiplier to SI is not possible
milliequivalentPerLiter concentration of charge (on dissolved ions). conversions must know the name of the ion; a single multiplier to SI is not possible
equivalentPerLiter concentration of charge (on dissolved ions). conversions must know the name of the ion; a single multiplier to SI is not possible
millimolePerGram millimoles per gram
molePerGram moles per gram
molePerKilogram moles per kilogram
micromolePerGram millimoles per gram
candelaPerMeterSquared candela Per Square Meter (1 lux)
footSquaredPerDay square feet per day
meterSquaredPerDay square meters per day
meterSquaredPerSecond meters squared per second, SI unit for kinematic viscosity, specific relative angular momentum and thermal diffusivity. The unit may be better understood when phrased as "meter per second times meter" (velocity of an object with respect to a position).
gramPerCentimeterSquaredPerSecond grams per square centimeter per second
gramPerDayPerHectare grams Per Hectare Squared Per Day
gramPerMeterSquaredPerYear grams per square meter per year
kilogramPerHectarePerYear kilograms Per Hectare Per Year
kilogramPerMeterSquaredPerSecond kilograms per square meter per second
kilogramPerMeterSquaredPerDay kilograms per square meter per day
gramPerMeterSquaredPerDay grams per square meter per day
milligramPerMeterSquaredPerDay milligram per square meter per day
kilogramPerMeterSquaredPerYear kilograms per square meter per year
molePerKilogramPerSecond moles per kilogram per second
nanomolePerGramPerSecond nanomoles Per Gram Per Second
nanomolePerGramPerHour nanomoles Per Gram Per Hour
nanomolePerGramPerDay nanomoles Per Gram Per day
micromolePerGramPerSecond micromoles Per Gram Per Second
micromolePerGramPerHour micromoles Per Gram Per Hour
micromolePerGramPerDay micromoles Per Gram Per day
gramPerYear grams Per Year
kilogramPerSecond kilograms per second
tonnePerYear tonnes Per Year
numberPerMeterSquared number per meter squared, e.g., for a population density.
numberPerKilometerSquared number per kilometer squared
numberPerHectare number per hectare
numberPerMeterCubed number per meter cubed
numberPerLiter number of entities per liter
numberPerMilliliter number of entities per milliliter
meterPerGram meters per gram
numberPerGram number of entities per gram
gramPerGram grams per gram
milligramPerKilogram milligrams per kilogram
microgramPerGram micrograms per gram
nanogramPerGram micrograms per gram
microgramPerGramPerHour micrograms per gram per hour
microgramPerGramPerDay micrograms per gram per day
microgramPerGramPerWeek micrograms per gram per week
nanogramPerGramPerHour nanoograms per gram per hour
meterCubedPerMeterCubed milliliters per liter
literPerLiter milliliters per liter
milliliterPerLiter milliliters per liter
microliterPerLiter milliliters per liter
nanoliterPerLiter milliliters per liter
molePerMole millimoles per mole
millimolePerMole millimoles per mole
micromolePerMole millimoles per mole
nanomolePerMole millimoles per mole
molePerKilogram micromoles per kilogram
millimolePerKilogram micromoles per kilogram
micromolePerKilogram micromoles per kilogram
nanomolePerKilogram micromoles per kilogram
percent percent, one part per hundred parts. a decimal ratio multipled by 100
permil permil, one part per thousand parts. a decimal ratio multipled by 1000
wattPerMeterSquared watts per square meter, also, 1 kilogram per second cubed (ie, a flux)
kilowattPerMeterSquared kilowatts per square meter
wattPerMeterSquaredPerSteradian watts per square meter, in a solid angle
microwattPerCentimeterSquaredPerSteradian watts per square centimeter, in a solid angle
wattPerMeterSquaredPerNanometer watts per square meter, per unit of wavelength
microwattPerCentimeterSquaredPerNanometer watts per square centimeter, per unit of wavelength
wattPerMeterSquaredPerNanometerPerSteradian watts per square meter, per unit of wavelength in a solid angle
microwattPerCentimeterSquaredPerNanometerPerSteradian microwatts per square centimeter, per unit of wavelength, in a solid angle
molePerMeterSquaredPerSecond micromoles per square meter per second
micromolePerMeterSquaredPerSecond micromoles per square meter per second
micromolePerCentimeterSquaredPerSecond micromoles per square centimeter per second
megajoulePerMeterSquaredPerDay megajoules per square meter per day
langleyPerDay Langley (Ly) per day. Ly is a unit of energy density = 41840 joule/m^2, = 1 calorie/cm^2