Added in API level 3

GeomagneticField


public class GeomagneticField
extends Object

java.lang.Object
   ↳ android.hardware.GeomagneticField


Estimates magnetic field at a given point on Earth, and in particular, to compute the magnetic declination from true north.

This uses the World Magnetic Model produced by the United States National Geospatial-Intelligence Agency. More details about the model can be found at http://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml. This class currently uses WMM-2020 which is valid until 2025, but should produce acceptable results for several years after that. Future versions of Android may use a newer version of the model.

Summary

Public constructors

GeomagneticField(float gdLatitudeDeg, float gdLongitudeDeg, float altitudeMeters, long timeMillis)

Estimate the magnetic field at a given point and time.

Public methods

float getDeclination()
float getFieldStrength()
float getHorizontalStrength()
float getInclination()
float getX()
float getY()
float getZ()

Inherited methods

Object clone()

Creates and returns a copy of this object.

boolean equals(Object obj)

Indicates whether some other object is "equal to" this one.

void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

final Class<?> getClass()

Returns the runtime class of this Object.

int hashCode()

Returns a hash code value for the object.

final void notify()

Wakes up a single thread that is waiting on this object's monitor.

final void notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String toString()

Returns a string representation of the object.

final void wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

GeomagneticField

Added in API level 3
public GeomagneticField (float gdLatitudeDeg, 
                float gdLongitudeDeg, 
                float altitudeMeters, 
                long timeMillis)

Estimate the magnetic field at a given point and time.

Parameters
gdLatitudeDeg float: Latitude in WGS84 geodetic coordinates -- positive is east.

gdLongitudeDeg float: Longitude in WGS84 geodetic coordinates -- positive is north.

altitudeMeters float: Altitude in WGS84 geodetic coordinates, in meters.

timeMillis long: Time at which to evaluate the declination, in milliseconds since January 1, 1970. (approximate is fine -- the declination changes very slowly).

Public methods

getDeclination

Added in API level 3
public float getDeclination ()

Returns
float The declination of the horizontal component of the magnetic field from true north, in degrees (i.e. positive means the magnetic field is rotated east that much from true north).

getFieldStrength

Added in API level 3
public float getFieldStrength ()

Returns
float Total field strength in nanoteslas.

getHorizontalStrength

Added in API level 3
public float getHorizontalStrength ()

Returns
float Horizontal component of the field strength in nanoteslas.

getInclination

Added in API level 3
public float getInclination ()

Returns
float The inclination of the magnetic field in degrees -- positive means the magnetic field is rotated downwards.

getX

Added in API level 3
public float getX ()

Returns
float The X (northward) component of the magnetic field in nanoteslas.

getY

Added in API level 3
public float getY ()

Returns
float The Y (eastward) component of the magnetic field in nanoteslas.

getZ

Added in API level 3
public float getZ ()

Returns
float The Z (downward) component of the magnetic field in nanoteslas.