org.geotools.measure

Class Units

Object

Units

public final class Units
extends Object

A set of units to use in addition of SI and NonSI.

Since:

2.1

Author:

Martin Desruisseaux (IRD)

Field Summary

Fields

Modifier and Type	Field and Description
static Unit<Angle>	DEGREE_MINUTE_SECOND Pseudo-unit for degree - minute - second.
static Unit<Time>	MONTH Time duration of 1/12 of a Units.YEAR.
static Unit<Length>	PIXEL Length of 1/72 of a USCustomary.INCH
static Unit<Dimensionless>	PPM Parts per million.
static Unit<Angle>	SEXAGESIMAL_DMS Pseudo-unit for sexagesimal degree.

Method Summary

Modifier and Type	Method and Description
static <Q extends Quantity<Q>> Unit<Q>	autoCorrect(Unit<Q> unit) Returns an equivalent unit instance based on the provided unit.
static boolean	equals(Unit<?> unit1, Unit<?> unit2) Checks whether two units can be considered equivalent.
static UnitConverter	getConverterToAny(Unit<?> fromUnit, Unit<?> toUnit) Gets a UnitConverter between two units, wrapping any raised exception in a IllegalArgumentException.
static UnitFormat	getDefaultFormat() Gets an instance of the default system-wide Unit format.
static Unit<?>	parseUnit(String name) Parses the text into an instance of unit
static String	toName(Unit<?> unit) Unit name, willing to use SimpleUnitFormat to look up appropriate label if a name has not been not defined.
static String	toSymbol(Unit<?> unit) Unit symbol, willing to use SimpleUnitFormat to look up appropriate label if required.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PIXEL

public static final Unit<Length> PIXEL

Length of 1/72 of a USCustomary.INCH

MONTH

public static final Unit<Time> MONTH

Time duration of 1/12 of a Units.YEAR.

SEXAGESIMAL_DMS

public static final Unit<Angle> SEXAGESIMAL_DMS

Pseudo-unit for sexagesimal degree. Numbers in this pseudo-unit has the following format:

sign - degrees - decimal point - minutes (two digits) - integer seconds (two digits) - fraction of seconds (any precision).

This unit is non-linear and not pratical for computation. Consequently, it should be avoid as much as possible. Unfortunatly, this pseudo-unit is extensively used in the EPSG database (code 9110).

DEGREE_MINUTE_SECOND

public static final Unit<Angle> DEGREE_MINUTE_SECOND

Pseudo-unit for degree - minute - second. Numbers in this pseudo-unit has the following format:

signed degrees (integer) - arc-minutes (integer) - arc-seconds (real, any precision).

This unit is non-linear and not pratical for computation. Consequently, it should be avoid as much as possible. Unfortunatly, this pseudo-unit is extensively used in the EPSG database (code 9107).

PPM

public static final Unit<Dimensionless> PPM

Parts per million.

Method Detail

getDefaultFormat

public static UnitFormat getDefaultFormat()

Gets an instance of the default system-wide Unit format. Use this method instead of SimpleUnitFormat.getInstance(), since custom Geotools units might not get registered if SimpleUnitFormat.getInstance() is directly accessed.

See Also:

GeoToolsUnitFormat#getInstance()

toName

public static String toName(Unit<?> unit)

Unit name, willing to use SimpleUnitFormat to look up appropriate label if a name has not been not defined.

This allows us to format units like PIXEL.

toSymbol

public static String toSymbol(Unit<?> unit)

Unit symbol, willing to use SimpleUnitFormat to look up appropriate label if required.

This allows us to format units like PIXEL.

autoCorrect

public static <Q extends Quantity<Q>> Unit<Q> autoCorrect(Unit<Q> unit)

Returns an equivalent unit instance based on the provided unit. First, it tries to get one of the reference units defined in the JSR363 implementation in use. Units are considered equivalent if the equals(Unit, Unit) method returns true. If no equivalent reference unit is defined, it returns the provided unit.

equals

public static final boolean equals(Unit<?> unit1,
                                   Unit<?> unit2)

Checks whether two units can be considered equivalent. TransformedUnits are considered equivalent if they have the same system unit and their conversion factors to the system unit produce the identity converter when the inverse of the second factor is concatenated with the first factor, considering the precision of a float number. For other types of units, the comparison is delegated to their normal equals method.

getConverterToAny

public static UnitConverter getConverterToAny(Unit<?> fromUnit,
                                              Unit<?> toUnit)

Gets a UnitConverter between two units, wrapping any raised exception in a IllegalArgumentException.

Throws:

IllegalArgumentException - if unit1 can't be converter to unit2

parseUnit

public static Unit<?> parseUnit(String name)

Parses the text into an instance of unit

Returns:

A unit instance

Throws:

ParserException - if any problem occurs while parsing the specified character sequence (e.g. illegal syntax).

UnsupportedOperationException - if the UnitFormat is unable to parse.

See Also:

UnitFormat.parse(CharSequence)