ucar.unidata.geoloc

Class Bearing

java.lang.Object

ucar.unidata.geoloc.Bearing

public class Bearing
extends java.lang.Object

Computes the distance, azimuth, and back azimuth between two lat-lon positions on the Earth's surface. Reference ellipsoid is the WGS-84 by default. You may use a default Earth (EarthEllipsoid.WGS84) or you may define your own using a ucar.unidata.geoloc.Earth object.

Constructor Summary

Constructors

Constructor and Description
Bearing(double azimuth, double backazimuth, double distance)

Method Summary

Modifier and Type	Method and Description
static Bearing	calculateBearing(double lat1, double lon1, double lat2, double lon2) Computes distance (in km), azimuth (degrees clockwise positive from North, 0 to 360), and back azimuth (degrees clockwise positive from North, 0 to 360), from latitude-longituide point pt1 to latitude-longituide pt2.
static Bearing	calculateBearing(Earth e, double lat1, double lon1, double lat2, double lon2) Computes distance (in km), azimuth (degrees clockwise positive from North, 0 to 360), and back azimuth (degrees clockwise positive from North, 0 to 360), from latitude-longituide point pt1 to latitude-longituide pt2.
static Bearing	calculateBearing(Earth e, LatLonPoint pt1, LatLonPoint pt2) Calculate the bearing between the 2 points.
static Bearing	calculateBearing(LatLonPoint pt1, LatLonPoint pt2) Calculate the bearing between the 2 points.
double	getAngle() Get the azimuth in degrees, 0 = north, clockwise positive
double	getBackAzimuth() Get the back azimuth in degrees, 0 = north, clockwise positive
double	getDistance() Get the distance in kilometers
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Bearing

public Bearing(double azimuth,
               double backazimuth,
               double distance)

Method Detail

calculateBearing

public static Bearing calculateBearing(double lat1,
                                       double lon1,
                                       double lat2,
                                       double lon2)

Computes distance (in km), azimuth (degrees clockwise positive from North, 0 to 360), and back azimuth (degrees clockwise positive from North, 0 to 360), from latitude-longituide point pt1 to latitude-longituide pt2. Uses default Earth object.

Parameters:

lat1 - Lat of point 1

lon1 - Lon of point 1

lat2 - Lat of point 2

lon2 - Lon of point 2

Returns:

a Bearing object with distance (in km), azimuth from pt1 to pt2 (degrees, 0 = north, clockwise positive)

calculateBearing

public static Bearing calculateBearing(Earth e,
                                       double lat1,
                                       double lon1,
                                       double lat2,
                                       double lon2)

Computes distance (in km), azimuth (degrees clockwise positive from North, 0 to 360), and back azimuth (degrees clockwise positive from North, 0 to 360), from latitude-longituide point pt1 to latitude-longituide pt2.

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

Reference ellipsoid is the WGS-84 ellipsoid.
See http://www.colorado.edu/geography/gcraft/notes/datum/elist.html

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

Parameters:

e - Earth object (defines radius and flattening)

lat1 - Lat of point 1

lon1 - Lon of point 1

lat2 - Lat of point 2

lon2 - Lon of point 2

Returns:

a Bearing object with distance (in km), azimuth from pt1 to pt2 (degrees, 0 = north, clockwise positive)

calculateBearing

public static Bearing calculateBearing(Earth e,
                                       LatLonPoint pt1,
                                       LatLonPoint pt2)

Calculate the bearing between the 2 points. See calculateBearing below.

Parameters:

e - Earth object (defines radius & flattening)

pt1 - Point 1

pt2 - Point 2

Returns:

The bearing

calculateBearing

public static Bearing calculateBearing(LatLonPoint pt1,
                                       LatLonPoint pt2)

Calculate the bearing between the 2 points. See calculateBearing below. Uses default Earth object.

Parameters:

pt1 - Point 1

pt2 - Point 2

Returns:

The bearing

getAngle

public double getAngle()

Get the azimuth in degrees, 0 = north, clockwise positive

Returns:

azimuth in degrees

getBackAzimuth

public double getBackAzimuth()

Get the back azimuth in degrees, 0 = north, clockwise positive

Returns:

back azimuth in degrees

getDistance

public double getDistance()

Get the distance in kilometers

Returns:

distance in km

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object