EML Unit Type Definitions
Philosophy of Units
The concept of "unit" represents one of the most fundamental
categories of metadata. The classic example of data entropy is the
case in which a reported numeric value loses meaning due to lack of
associated units. Much of Ecology is driven by measurement, and
most measurements are inherently comparative. Good data description
requires a representation of the basis for comparison, i.e., the
unit. In modeling units, the authors of EML drew
inspiration from the
NIST Reference on Constants, Units, and Uncertainty
.
This document defines a unit as "a particular physical quantity,
defined and adopted by convention, with which other particular
quantities of the same kind are compared to express their value."
The authors of the EML 2 specification (hereafter "the authors")
decided to make the unit element required, wherever
possible.
The units are defined in the
STMML language
in a document that is shipped with each release of
EML. See the accompanying STMML file, eml-unitDictionary.xml, for
precise, quantitative definitions of each of these units and their
relationships to base SI units
which modules use these types (and which could but dont yet?)
anything else?
Module details
| Recommended Usage: | any module that needs units |
| Stand-alone: | no |
| Imports: | eml-documentation |
| Imported By: | |
Simple Type Definitions:
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StandardUnitDictionary
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The unitDictionary is the standard set
of units included with the EML distribution, mainly from the
SI standard. These unit names should be used in the standardUnit field to
describe an attribute. See the accompanying STMML file, eml-unitDictionary.xml, for
precise, quantitative definitions of each of these units and their
relationships to base SI units.
The standard Unit Dictionary is built from a union of simpleTypes.
This construct allows unit types to be used individually as appropriate
in EML content (e.g., LengthUnitType for distances )
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LengthUnitType
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Derived from: xs:string (by xs:restriction)
Allowed values:
- meter
- nanometer
- micrometer
- micron
- millimeter
- centimeter
- decimeter
- dekameter
- hectometer
- kilometer
- megameter
- angstrom
- inch
- Foot_US
- foot
- Foot_Gold_Coast
- fathom
- nauticalMile
- yard
- Yard_Indian
- Link_Clarke
- Yard_Sears
- mile
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The LengthUnitType is the enumerated list of units which are of length type, or have a parentSI of meter.
These unit names can be used where ever content should be restricted to a length, such as a distance or
altitude. The units are defined in the STMML
language in a document that is shipped with each release of
EML called eml-unitDictionary.xml. See this file for
precise, quantitative definitions of each of these units and their
relationships to base SI units.
|
MassUnitType
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|
Derived from: xs:string (by xs:restriction)
Allowed values:
- kilogram
- nanogram
- microgram
- milligram
- centigram
- decigram
- gram
- dekagram
- hectogram
- megagram
- tonne
- pound
- ton
|
The MassUnitType is the enumerated list of units which are of mass type, or have a parentSI of kilogram.
These unit names can be used where ever content should be restricted to a mass, such as an amount.
The units are defined in the STMML
language in a document that is shipped with each release of
EML called eml-unitDictionary.xml. See this file for
precise, quantitative definitions of each of these units and their
relationships to base SI units.
|
otherUnitType
|
|
Derived from: xs:string (by xs:restriction)
Allowed values:
- dimensionless
- second
- kelvin
- coulomb
- ampere
- mole
- candela
- number
- radian
- degree
- grad
- cubicMeter
- nominalMinute
- nominalHour
- nominalDay
- nominalWeek
- nominalYear
- nominalLeapYear
- celsius
- fahrenheit
- nanosecond
- microsecond
- millisecond
- centisecond
- decisecond
- dekasecond
- hectosecond
- kilosecond
- megasecond
- minute
- hour
- kiloliter
- microliter
- milliliter
- liter
- gallon
- quart
- bushel
- cubicInch
- pint
- megahertz
- kilohertz
- hertz
- millihertz
- newton
- joule
- calorie
- britishThermalUnit
- footPound
- lumen
- lux
- becquerel
- gray
- sievert
- katal
- henry
- megawatt
- kilowatt
- watt
- milliwatt
- megavolt
- kilovolt
- volt
- millivolt
- farad
- ohm
- ohmMeter
- siemen
- weber
- tesla
- pascal
- megapascal
- kilopascal
- atmosphere
- bar
- millibar
- kilogramsPerSquareMeter
- gramsPerSquareMeter
- milligramsPerSquareMeter
- kilogramsPerHectare
- tonnePerHectare
- poundsPerSquareInch
- kilogramPerCubicMeter
- milliGramsPerMilliLiter
- gramsPerLiter
- milligramsPerCubicMeter
- microgramsPerLiter
- milligramsPerLiter
- gramsPerCubicCentimeter
- gramsPerMilliliter
- gramsPerLiterPerDay
- litersPerSecond
- cubicMetersPerSecond
- cubicFeetPerSecond
- squareMeter
- are
- hectare
- squareKilometers
- squareMillimeters
- squareCentimeters
- acre
- squareFoot
- squareYard
- squareMile
- litersPerSquareMeter
- bushelsPerAcre
- litersPerHectare
- squareMeterPerKilogram
- metersPerSecond
- metersPerDay
- feetPerDay
- feetPerSecond
- feetPerHour
- yardsPerSecond
- milesPerHour
- milesPerSecond
- milesPerMinute
- centimetersPerSecond
- millimetersPerSecond
- centimeterPerYear
- knots
- kilometersPerHour
- metersPerSecondSquared
- waveNumber
- cubicMeterPerKilogram
- cubicMicrometersPerGram
- amperePerSquareMeter
- amperePerMeter
- molePerCubicMeter
- molarity
- molality
- candelaPerSquareMeter
- metersSquaredPerSecond
- metersSquaredPerDay
- feetSquaredPerDay
- kilogramsPerMeterSquaredPerSecond
- gramsPerCentimeterSquaredPerSecond
- gramsPerMeterSquaredPerYear
- gramsPerHectarePerDay
- kilogramsPerHectarePerYear
- kilogramsPerMeterSquaredPerYear
- molesPerKilogram
- molesPerGram
- millimolesPerGram
- molesPerKilogramPerSecond
- nanomolesPerGramPerSecond
- kilogramsPerSecond
- tonnesPerYear
- gramsPerYear
- numberPerMeterSquared
- numberPerKilometerSquared
- numberPerMeterCubed
- numberPerLiter
- numberPerMilliliter
- metersPerGram
- numberPerGram
- gramsPerGram
- microgramsPerGram
- cubicCentimetersPerCubicCentimeters
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The unitDictionary is the standard set
of units included with the EML distribution, mainly from the
SI standard. These unit names can be used in the standardUnit field to
describe an attribute. The units are defined in the STMML
language in a document that is shipped with each release of
EML. See the accompanying STMML file eml-unitDictionary.xml for
precise, quantitative definitions of each of these units and their
relationships to base SI units.
The standard Unit Dictionary is built from a union of simpleTypes. This Type
enumerates the units which are not in other Type definitions, but are to be
included as standard.
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angleUnitType
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Derived from: xs:string (by xs:restriction)
Allowed values:
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The AngleUnitType is the enumerated list of angle units. For example,
plane angle (radian, rad) and solid angle (steradian, sr) are actually
dimensionless, and their symbols used as appropriate
(e.g, sr in photometry). These unit names could be used where
ever content should be restricted.
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Web Contact: jones@nceas.ucsb.edu