org.apache.lucene.spatial.util

Class GeoProjectionUtils

java.lang.Object

org.apache.lucene.spatial.util.GeoProjectionUtils

public class GeoProjectionUtils
extends Object

Reusable geo-spatial projection utility methods.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields

Modifier and Type	Field and Description
static double	ECCENTRICITY first eccentricity (e)
static double	FLATTENING earth flattening factor (f)
static double	MAX_LAT_RADIANS max latitude value in radians
static double	MAX_LON_RADIANS max longitude value in radians
static double	MIN_LAT_RADIANS min latitude value in radians
static double	MIN_LON_RADIANS min longitude value in radians
static double	SEMIMAJOR_AXIS major (a) axis in meters
static double	SEMIMAJOR_AXIS2 major axis squared (a2)
static double	SEMIMINOR_AXIS minor (b) axis in meters
static double	SEMIMINOR_AXIS2 minor axis squared (b2)

Method Summary

Modifier and Type	Method and Description
static double	bearingGreatCircle(double lat1, double lon1, double lat2, double lon2) Finds the bearing (in degrees) between 2 geo points (lat, lon) using great circle arc
static double[]	llaToECF(double lat, double lon, double alt, double[] ecf) Converts from geodesic lat lon alt to geocentric earth-centered earth-fixed
static double[]	pointFromLonLatBearingGreatCircle(double lat, double lon, double bearing, double dist, double[] pt) Finds a point along a bearing from a given lat,lon geolocation using great circle arc

Methods inherited from class java.lang.Object

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

Field Detail

SEMIMAJOR_AXIS

public static final double SEMIMAJOR_AXIS

major (a) axis in meters

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Constant Field Values

FLATTENING

public static final double FLATTENING

earth flattening factor (f)

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Constant Field Values

SEMIMINOR_AXIS

public static final double SEMIMINOR_AXIS

minor (b) axis in meters

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Constant Field Values

ECCENTRICITY

public static final double ECCENTRICITY

first eccentricity (e)

SEMIMAJOR_AXIS2

public static final double SEMIMAJOR_AXIS2

major axis squared (a2)

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Constant Field Values

SEMIMINOR_AXIS2

public static final double SEMIMINOR_AXIS2

minor axis squared (b2)

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Constant Field Values

MIN_LON_RADIANS

public static final double MIN_LON_RADIANS

min longitude value in radians

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Constant Field Values

MIN_LAT_RADIANS

public static final double MIN_LAT_RADIANS

min latitude value in radians

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Constant Field Values

MAX_LON_RADIANS

public static final double MAX_LON_RADIANS

max longitude value in radians

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Constant Field Values

MAX_LAT_RADIANS

public static final double MAX_LAT_RADIANS

max latitude value in radians

See Also:

Constant Field Values

Method Detail

llaToECF

public static final double[] llaToECF(double lat,
                                      double lon,
                                      double alt,
                                      double[] ecf)

Converts from geodesic lat lon alt to geocentric earth-centered earth-fixed

Parameters:

lat - geodesic latitude

lon - geodesic longitude

alt - geodesic altitude

ecf - reusable earth-centered earth-fixed result

Returns:

either a new ecef array or the reusable ecf parameter

pointFromLonLatBearingGreatCircle

public static final double[] pointFromLonLatBearingGreatCircle(double lat,
                                                               double lon,
                                                               double bearing,
                                                               double dist,
                                                               double[] pt)

Finds a point along a bearing from a given lat,lon geolocation using great circle arc

Parameters:

lat - origin latitude in degrees

lon - origin longitude in degrees

bearing - azimuthal bearing in degrees

dist - distance in meters

pt - resulting point

Returns:

the point along a bearing at a given distance in meters

bearingGreatCircle

public static double bearingGreatCircle(double lat1,
                                        double lon1,
                                        double lat2,
                                        double lon2)

Finds the bearing (in degrees) between 2 geo points (lat, lon) using great circle arc

Parameters:

lat1 - first point latitude in degrees

lon1 - first point longitude in degrees

lat2 - second point latitude in degrees

lon2 - second point longitude in degrees

Returns:

the bearing (in degrees) between the two provided points