gov.nasa.worldwind.geom
Class LatLon

java.lang.Object
  gov.nasa.worldwind.geom.LatLon

public class LatLon
extends Object

Represents a point on the two-dimensional surface of a globe. Latitude is the degrees North and ranges between [-90, 90], while longitude refers to degrees East, and ranges between (-180, 180].

Instances of LatLon are immutable.

Field Summary

static LatLon

ZERO

Constructor Summary

LatLon(Angle latitude, Angle longitude)
Contructs a new LatLon from two angles.

Method Summary

LatLon	add(LatLon that)
LatLon	add(Position that)
static Angle	azimuth(LatLon p1, LatLon p2)
static double	ellipsoidalDistance(LatLon p1, LatLon p2, double equatorialRadius, double polarRadius) Computes the distance between two points on an ellipsoid iteratively.
Angle	ellipsoidalForwardAzimuth(LatLon p1, LatLon p2, double equatorialRadius, double polarRadius) Compute the forward azimuth between two positions
static LatLon	endPosition(LatLon p, double azimuthRadians, double pathLengthRadians)
boolean	equals(Object o)
static LatLon	fromDegrees(double latitude, double longitude) Factory method for obtaining a new LatLon from two angles expressed in degrees.
static LatLon	fromRadians(double latitude, double longitude) Factor method for obtaining a new LatLon from two angles expressed in radians.
Angle	getLatitude() Obtains the latitude of this LatLon.
Angle	getLongitude() Obtains the longitude of this LatLon.
int	hashCode()
static LatLon	interpolate(double amount, LatLon value1, LatLon value2)
static boolean	positionsCrossDateLine(Iterable<LatLon> positions)
static boolean	positionsCrossLongitudeBoundary(LatLon p1, LatLon p2)
static Angle	sphericalDistance(LatLon p1, LatLon p2) Computes the great circle angular distance between two locations.
LatLon	subtract(LatLon that)
LatLon	subtract(Position that)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

ZERO

public static final LatLon ZERO

Constructor Detail

LatLon

public LatLon(Angle latitude,
              Angle longitude)

Contructs a new LatLon from two angles. Neither angle may be null.

Parameters:

latitude - latitude

longitude - longitude

Throws:

IllegalArgumentException - if latitude or longitude is null

Method Detail

add

public LatLon add(LatLon that)

add

public LatLon add(Position that)

azimuth

public static Angle azimuth(LatLon p1,
                            LatLon p2)

ellipsoidalDistance

public static double ellipsoidalDistance(LatLon p1,
                                         LatLon p2,
                                         double equatorialRadius,
                                         double polarRadius)

Computes the distance between two points on an ellipsoid iteratively.

NOTE: This method was copied from the UniData NetCDF Java library. http://www.unidata.ucar.edu/software/netcdf-java/

Algorithm from U.S. National Geodetic Survey, FORTRAN program "inverse," subroutine "INVER1," by L. PFEIFER and JOHN G. GERGEN. See http://www.ngs.noaa.gov/TOOLS/Inv_Fwd/Inv_Fwd.html

Original documentation: SOLUTION OF THE GEODETIC INVERSE PROBLEM AFTER T.VINCENTY MODIFIED RAINSFORD'S METHOD WITH HELMERT'S ELLIPTICAL TERMS EFFECTIVE IN ANY AZIMUTH AND AT ANY DISTANCE SHORT OF ANTIPODAL STANDPOINT/FOREPOINT MUST NOT BE THE GEOGRAPHIC POLE

Requires close to 1.4 E-5 seconds wall clock time per call on a 550 MHz Pentium with Linux 7.2.

Parameters:

p1 - first position

p2 - second position

equatorialRadius - the equatorial radius of the globe in meters

polarRadius - the polar radius of the globe in meters

Returns:

distance in meters between the two points

ellipsoidalForwardAzimuth

public Angle ellipsoidalForwardAzimuth(LatLon p1,
                                       LatLon p2,
                                       double equatorialRadius,
                                       double polarRadius)

Compute the forward azimuth between two positions

Parameters:

p1 - first position

p2 - second position

equatorialRadius - the equatorial radius of the globe in meters

polarRadius - the polar radius of the globe in meters

Returns:

the azimuth

endPosition

public static LatLon endPosition(LatLon p,
                                 double azimuthRadians,
                                 double pathLengthRadians)

equals

public boolean equals(Object o)

Overrides:

equals in class Object

fromDegrees

public static LatLon fromDegrees(double latitude,
                                 double longitude)

Factory method for obtaining a new LatLon from two angles expressed in degrees.

Parameters:

latitude - in degrees

longitude - in degrees

Returns:

a new LatLon from the given angles, which are expressed as degrees

fromRadians

public static LatLon fromRadians(double latitude,
                                 double longitude)

Factor method for obtaining a new LatLon from two angles expressed in radians.

Parameters:

latitude - in radians

longitude - in radians

Returns:

a new LatLon from the given angles, which are expressed as radians

getLatitude

public final Angle getLatitude()

Obtains the latitude of this LatLon.

Returns:

this LatLon's latitude

getLongitude

public final Angle getLongitude()

Obtains the longitude of this LatLon.

Returns:

this LatLon's longitude

hashCode

public int hashCode()

Overrides:

hashCode in class Object

interpolate

public static LatLon interpolate(double amount,
                                 LatLon value1,
                                 LatLon value2)

positionsCrossDateLine

public static boolean positionsCrossDateLine(Iterable<LatLon> positions)

positionsCrossLongitudeBoundary

public static boolean positionsCrossLongitudeBoundary(LatLon p1,
                                                      LatLon p2)

sphericalDistance

public static Angle sphericalDistance(LatLon p1,
                                      LatLon p2)

Computes the great circle angular distance between two locations. The return value gives the distance as the angle between the two positions on the pi radius circle. In radians, this angle is also the arc length of the segment between the two positions on that circle. To compute a distance in meters from this value, multiply it by the radius of the globe.

Parameters:

p1 - LatLon of the first location

p2 - LatLon of the second location

Returns:

the angular distance between the two locations. In radians, this value is the arc length of the radius pi circle.

subtract

public LatLon subtract(LatLon that)

subtract

public LatLon subtract(Position that)

toString

public String toString()

Overrides:

toString in class Object