java.lang.Object
- org.openstreetmap.josm.data.SystemOfMeasurement

```
public class SystemOfMeasurement
extends java.lang.Object
```
A system of units used to express length and area measurements.
This class also manages one globally set system of measurement stored in the ProjectionPreference

Since:

3406 (creation), 6992 (extraction in this package)

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static interface SystemOfMeasurement.SoMChangeListener
Interface to notify listeners of the change of the system of measurement.

Field Summary

Fields
Modifier and Type	Field	Description
`static java.util.Map<java.lang.String,SystemOfMeasurement>`	`ALL_SYSTEMS`	Known systems of measurement.
`java.lang.String`	`aName`	First unit used to format text.
`java.lang.String`	`areaCustomName`	Specific optional area unit.
`double`	`areaCustomValue`	Specific optional area value, in squared meters, between `aValueaValue` and `bValuebValue`.
`double`	`aValue`	First value, in meters, used to translate unit according to above formula.
`java.lang.String`	`bName`	Second unit used to format text.
`double`	`bValue`	Second value, in meters, used to translate unit according to above formula.
`static SystemOfMeasurement`	`CHINESE`	Chinese system.
`static SystemOfMeasurement`	`IMPERIAL`	Imperial system (British Commonwealth and former British Empire).
`static SystemOfMeasurement`	`METRIC`	Metric system (international standard).
`private java.lang.String`	`name`	Translatable name of this system of measurement.
`static SystemOfMeasurement`	`NAUTICAL_MILE`	Nautical mile system (navigation, polar exploration).
`static StringProperty`	`PROP_SYSTEM_OF_MEASUREMENT`	Preferences entry for system of measurement.
`private static java.util.concurrent.CopyOnWriteArrayList<SystemOfMeasurement.SoMChangeListener>`	`somChangeListeners`
`java.lang.String`	`speedName`	Most common speed symbol (kmh/h, mph, kn, etc.)
`double`	`speedValue`	Speed value for the most common speed symbol, in meters per second

Constructor Summary

Constructors
Constructor	Description
`SystemOfMeasurement(java.lang.String name, double aValue, java.lang.String aName, double bValue, java.lang.String bName, java.lang.String speedName, double speedValue)`	System of measurement.
`SystemOfMeasurement(java.lang.String name, double aValue, java.lang.String aName, double bValue, java.lang.String bName, java.lang.String speedName, double speedValue, double areaCustomValue, java.lang.String areaCustomName)`	System of measurement.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static void`	`addSoMChangeListener(SystemOfMeasurement.SoMChangeListener listener)`	Adds a SoM change listener.
`protected static void`	`fireSoMChanged(java.lang.String oldSoM, java.lang.String newSoM)`
`private static java.lang.String`	`formatText(double v, java.lang.String unit, java.text.NumberFormat format)`
`java.lang.String`	`getAreaText(double area)`	Returns the text describing the given area in this system of measurement.
`java.lang.String`	`getAreaText(double area, java.text.NumberFormat format, double threshold)`	Returns the text describing the given area in this system of measurement.
`static SystemOfMeasurement`	`getDefault()`	Returns the default system of measurement for the current country.
`java.lang.String`	`getDistText(double dist)`	Returns the text describing the given distance in this system of measurement.
`java.lang.String`	`getDistText(double dist, java.text.NumberFormat format, double threshold)`	Returns the text describing the given distance in this system of measurement.
`java.lang.String`	`getName()`	Returns the translatable name of this system of measurement.
`static SystemOfMeasurement`	`getSystemOfMeasurement()`	Returns the current global system of measurement.
`static void`	`removeSoMChangeListener(SystemOfMeasurement.SoMChangeListener listener)`	Removes a global SoM change listener.
`static void`	`setSystemOfMeasurement(SystemOfMeasurement som)`	Sets the current global system of measurement.
`java.lang.String`	`toString()`	Returns the localized name of this system of measurement

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - METRIC
```
public static final SystemOfMeasurement METRIC
```
    Metric system (international standard).
    
    Since:
    
    3406
  - CHINESE
```
public static final SystemOfMeasurement CHINESE
```
    Chinese system. See length units, area units
    
    Since:
    
    3406
  - IMPERIAL
```
public static final SystemOfMeasurement IMPERIAL
```
    Imperial system (British Commonwealth and former British Empire).
    
    Since:
    
    3406
  - NAUTICAL_MILE
```
public static final SystemOfMeasurement NAUTICAL_MILE
```
    Nautical mile system (navigation, polar exploration).
    
    Since:
    
    5549
  - ALL_SYSTEMS
```
public static final java.util.Map<java.lang.String,SystemOfMeasurement> ALL_SYSTEMS
```
    Known systems of measurement.
    
    Since:
    
    3406
  - PROP_SYSTEM_OF_MEASUREMENT
```
public static final StringProperty PROP_SYSTEM_OF_MEASUREMENT
```
    Preferences entry for system of measurement.
    
    Since:
    
    12674 (moved from ProjectionPreference)
  - somChangeListeners
```
private static final java.util.concurrent.CopyOnWriteArrayList<SystemOfMeasurement.SoMChangeListener> somChangeListeners
```
  - name
```
private final java.lang.String name
```
    Translatable name of this system of measurement.
  - aValue
```
public final double aValue
```
    First value, in meters, used to translate unit according to above formula.
  - bValue
```
public final double bValue
```
    Second value, in meters, used to translate unit according to above formula.
  - aName
```
public final java.lang.String aName
```
    First unit used to format text.
  - bName
```
public final java.lang.String bName
```
    Second unit used to format text.
  - speedValue
```
public final double speedValue
```
    Speed value for the most common speed symbol, in meters per second
    
    Since:
    
    10175
  - speedName
```
public final java.lang.String speedName
```
    Most common speed symbol (kmh/h, mph, kn, etc.)
    
    Since:
    
    10175
  - areaCustomValue
```
public final double areaCustomValue
```
    Specific optional area value, in squared meters, between aValue*aValue and bValue*bValue. Set to -1 if not used.
    
    Since:
    
    5870
  - areaCustomName
```
public final java.lang.String areaCustomName
```
    Specific optional area unit. Set to null if not used.
    
    Since:
    
    5870
- Constructor Detail
  - SystemOfMeasurement
```
public SystemOfMeasurement(java.lang.String name,
                           double aValue,
                           java.lang.String aName,
                           double bValue,
                           java.lang.String bName,
                           java.lang.String speedName,
                           double speedValue)
```
    System of measurement. Currently covers only length (and area) units. If a quantity x is given in m (x_m) and in unit a (x_a) then it translates as x_a == x_m / aValue
    
    Parameters:
    
    name - Translatable name of this system of measurement
    
    aValue - First value, in meters, used to translate unit according to above formula.
    
    aName - First unit used to format text.
    
    bValue - Second value, in meters, used to translate unit according to above formula.
    
    bName - Second unit used to format text.
    
    speedName - the most common speed symbol (kmh/h, mph, kn, etc.)
    
    speedValue - the speed value for the most common speed symbol, for 1 meter per second
    
    Since:
    
    15395
  - SystemOfMeasurement
```
public SystemOfMeasurement(java.lang.String name,
                           double aValue,
                           java.lang.String aName,
                           double bValue,
                           java.lang.String bName,
                           java.lang.String speedName,
                           double speedValue,
                           double areaCustomValue,
                           java.lang.String areaCustomName)
```
    System of measurement. Currently covers only length (and area) units. If a quantity x is given in m (x_m) and in unit a (x_a) then it translates as x_a == x_m / aValue
    
    Parameters:
    
    name - Translatable name of this system of measurement
    
    aValue - First value, in meters, used to translate unit according to above formula.
    
    aName - First unit used to format text.
    
    bValue - Second value, in meters, used to translate unit according to above formula.
    
    bName - Second unit used to format text.
    
    speedName - the most common speed symbol (kmh/h, mph, kn, etc.)
    
    speedValue - the speed value for the most common speed symbol, for 1 meter per second
    
    areaCustomValue - Specific optional area value, in squared meters, between aValue*aValue and bValue*bValue. Set to -1 if not used.
    
    areaCustomName - Specific optional area unit. Set to null if not used.
    
    Since:
    
    15395
- Method Detail
  - removeSoMChangeListener
```
public static void removeSoMChangeListener(SystemOfMeasurement.SoMChangeListener listener)
```
    Removes a global SoM change listener.
    
    Parameters:
    
    listener - the listener. Ignored if null or already absent
    
    Since:
    
    8554
  - addSoMChangeListener
```
public static void addSoMChangeListener(SystemOfMeasurement.SoMChangeListener listener)
```
    Adds a SoM change listener.
    
    Parameters:
    
    listener - the listener. Ignored if null or already registered.
    
    Since:
    
    8554
  - fireSoMChanged
```
protected static void fireSoMChanged(java.lang.String oldSoM,
                                     java.lang.String newSoM)
```
  - getSystemOfMeasurement
```
public static SystemOfMeasurement getSystemOfMeasurement()
```
    Returns the current global system of measurement.
    
    Returns:
    
    The current system of measurement (metric system by default).
    
    Since:
    
    8554
  - setSystemOfMeasurement
```
public static void setSystemOfMeasurement(SystemOfMeasurement som)
```
    Sets the current global system of measurement.
    
    Parameters:
    
    som - The system of measurement to set. Must be defined in ALL_SYSTEMS.
    
    Throws:
    
    java.lang.IllegalArgumentException - if som is not known
    
    Since:
    
    16985 (signature)
  - getDistText
```
public java.lang.String getDistText(double dist)
```
    Returns the text describing the given distance in this system of measurement.
    
    Parameters:
    
    dist - The distance in metres
    
    Returns:
    
    The text describing the given distance in this system of measurement.
  - getDistText
```
public java.lang.String getDistText(double dist,
                                    java.text.NumberFormat format,
                                    double threshold)
```
    Returns the text describing the given distance in this system of measurement.
    
    Parameters:
    
    dist - The distance in metres
    
    format - A NumberFormat to format the area value
    
    threshold - Values lower than this threshold are displayed as "< [threshold]"
    
    Returns:
    
    The text describing the given distance in this system of measurement.
    
    Since:
    
    6422
  - getAreaText
```
public java.lang.String getAreaText(double area)
```
    Returns the text describing the given area in this system of measurement.
    
    Parameters:
    
    area - The area in square metres
    
    Returns:
    
    The text describing the given area in this system of measurement.
    
    Since:
    
    5560
  - getAreaText
```
public java.lang.String getAreaText(double area,
                                    java.text.NumberFormat format,
                                    double threshold)
```
    Returns the text describing the given area in this system of measurement.
    
    Parameters:
    
    area - The area in square metres
    
    format - A NumberFormat to format the area value
    
    threshold - Values lower than this threshold are displayed as "< [threshold]"
    
    Returns:
    
    The text describing the given area in this system of measurement.
    
    Since:
    
    6422
  - getName
```
public java.lang.String getName()
```
    Returns the translatable name of this system of measurement.
    
    Returns:
    
    the translatable name of this system of measurement
    
    Since:
    
    15395
  - toString
```
public java.lang.String toString()
```
    Returns the localized name of this system of measurement
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the localized name
  - getDefault
```
public static SystemOfMeasurement getDefault()
```
    Returns the default system of measurement for the current country.
    
    Returns:
    
    the default system of measurement for the current country
    
    Since:
    
    15395
  - formatText
```
private static java.lang.String formatText(double v,
                                           java.lang.String unit,
                                           java.text.NumberFormat format)
```

Class SystemOfMeasurement

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

METRIC

CHINESE

IMPERIAL

NAUTICAL_MILE

ALL_SYSTEMS

PROP_SYSTEM_OF_MEASUREMENT

somChangeListeners

name

aValue

bValue

aName

bName

speedValue

speedName

areaCustomValue

areaCustomName

Constructor Detail

SystemOfMeasurement

SystemOfMeasurement

Method Detail

removeSoMChangeListener

addSoMChangeListener

fireSoMChanged

getSystemOfMeasurement

setSystemOfMeasurement

getDistText

getDistText

getAreaText

getAreaText

getName

toString

getDefault

formatText