org.opensha.commons.geo
Class GeoTools

java.lang.Object
  org.opensha.commons.geo.GeoTools

public class GeoTools
extends Object

This class provides static references to constants and conversions useful for geographic calculations, as well as a variety of utility methods.

Version:

$Id: GeoTools.java 8912 2012-04-20 17:29:53Z pmpowers $

Author:

Peter Powers

Field Summary

static double	DEPTH_MAX Maximum earthquake depth value (700 km) used for range checking.
static double	DEPTH_MIN Minimum earthquake depth value (-5 km) used for range checking.
static double	EARTH_RADIUS_EQUATORIAL The equatorial radius of the earth [6378.1370 km] (see Wikipedia) as derived from the WGS-84 ellipsoid.
static double	EARTH_RADIUS_MEAN The Authalic mean radius (Ar) of the earth [6371.0072 km] (see Wikipedia).
static double	EARTH_RADIUS_POLAR The polar radius of the earth [6356.7523 km] (see Wikipedia) as derived from the WGS-84 ellipsoid.
static double	LAT_MAX Maximum latitude value (90°) used for range checking.
static double	LAT_MIN Minimum latitude value (-90°) used for range checking.
static double	LON_MAX Maximum longitude value (180°) used for range checking.
static double	LON_MIN Minimum longitude value (-180°) used for range checking.
static double	MINUTES_PER_DEGREE Convenience constant for arcminutes per degree (60).
static double	PI_BY_2 Convenience constant for PI / 2
static double	SECONDS_PER_DEGREE Convenience constant for arcseconds per degree (3600).
static double	TO_DEG Conversion multiplier for radians to degrees
static double	TO_RAD Conversion multiplier for degrees to radians
static double	TWOPI Convenience constant for 2 * PI

Constructor Summary

GeoTools()

Method Summary

static double	degreesLatPerKm(Location p) Returns the number of degrees of latitude per km at a given Location.
static double	degreesLonPerKm(Location p) Returns the number of degrees of longitude per km at a given Location.
static double	minutesToDeg(double minutes) Converts arcminutes to decimal degrees.
static double	radiusAtLocation(Location p) Returns the radius of the earth at the latitude of the supplied Location (see Wikipedia for source).
static double	secondsToDeg(double seconds) Converts arcseconds to decimal degrees.
static double	toDecimalDegrees(double degrees, double minutes) Converts 'degree : decimal minutes' to decimal degrees.
static void	validateDepth(double depth) Verifies that a depth value falls within range of DEPTH_MIN and DEPTH_MAX (inclusive).
static void	validateDepths(double[] depths) Verifies that a set of depth values fall within range of DEPTH_MIN and DEPTH_MAX (inclusive).
static void	validateLat(double lat) Verifies that a latitude value falls within range of LAT_MIN and LAT_MAX (inclusive).
static void	validateLats(double[] lats) Verifies that an array of latitude values fall within range of LAT_MIN and LAT_MAX (inclusive).
static void	validateLon(double lon) Verifies that a longitude value falls within range of LON_MIN and LON_MAX (inclusive).
static void	validateLons(double[] lons) Verifies that a set of longitude values fall within range of LON_MIN and LON_MAX (inclusive).

Methods inherited from class java.lang.Object

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

Field Detail

EARTH_RADIUS_MEAN

public static final double EARTH_RADIUS_MEAN

The Authalic mean radius (Ar) of the earth [6371.0072 km] (see Wikipedia).

See Also:

Constant Field Values

EARTH_RADIUS_EQUATORIAL

public static final double EARTH_RADIUS_EQUATORIAL

The equatorial radius of the earth [6378.1370 km] (see Wikipedia) as derived from the WGS-84 ellipsoid.

See Also:

Constant Field Values

EARTH_RADIUS_POLAR

public static final double EARTH_RADIUS_POLAR

The polar radius of the earth [6356.7523 km] (see Wikipedia) as derived from the WGS-84 ellipsoid.

See Also:

Constant Field Values

LAT_MIN

public static final double LAT_MIN

Minimum latitude value (-90°) used for range checking.

See Also:

Constant Field Values

LAT_MAX

public static final double LAT_MAX

Maximum latitude value (90°) used for range checking.

See Also:

Constant Field Values

LON_MIN

public static final double LON_MIN

Minimum longitude value (-180°) used for range checking.

See Also:

Constant Field Values

LON_MAX

public static final double LON_MAX

Maximum longitude value (180°) used for range checking.

See Also:

Constant Field Values

DEPTH_MIN

public static final double DEPTH_MIN

Minimum earthquake depth value (-5 km) used for range checking. This follows the positive-down depth convention of seismology.

See Also:

Constant Field Values

DEPTH_MAX

public static final double DEPTH_MAX

Maximum earthquake depth value (700 km) used for range checking. This follows the positive-down depth convention of seismology.

See Also:

Constant Field Values

TO_RAD

public static final double TO_RAD

Conversion multiplier for degrees to radians

TO_DEG

public static final double TO_DEG

Conversion multiplier for radians to degrees

TWOPI

public static final double TWOPI

Convenience constant for 2 * PI

See Also:

Constant Field Values

PI_BY_2

public static final double PI_BY_2

Convenience constant for PI / 2

See Also:

Constant Field Values

SECONDS_PER_DEGREE

public static final double SECONDS_PER_DEGREE

Convenience constant for arcseconds per degree (3600).

See Also:

Constant Field Values

MINUTES_PER_DEGREE

public static final double MINUTES_PER_DEGREE

Convenience constant for arcminutes per degree (60).

See Also:

Constant Field Values

Constructor Detail

GeoTools

public GeoTools()

Method Detail

validateLats

public static final void validateLats(double[] lats)

Verifies that an array of latitude values fall within range of LAT_MIN and LAT_MAX (inclusive).

Parameters:

lats - latitudes to validate

Throws:

NullPointerException - if lats is null

IllegalArgumentException - if any lats value is out of range

See Also:

DataUtils.validate(double, double, double...)

validateLat

public static final void validateLat(double lat)

Verifies that a latitude value falls within range of LAT_MIN and LAT_MAX (inclusive).

Parameters:

lat - latitude to validate

Throws:

IllegalArgumentException - if lat value is out of range

See Also:

DataUtils.validate(double, double, double)

validateLons

public static void validateLons(double[] lons)

Verifies that a set of longitude values fall within range of LON_MIN and LON_MAX (inclusive).

Parameters:

lons - longitudes to validate

Throws:

IllegalArgumentException - if any lons value is out of range

See Also:

DataUtils.validate(double, double, double...)

validateLon

public static void validateLon(double lon)

Verifies that a longitude value falls within range of LON_MIN and LON_MAX (inclusive).

Parameters:

lon - longitude to validate

Throws:

IllegalArgumentException - if lon value is out of range

See Also:

DataUtils.validate(double, double, double)

validateDepths

public static void validateDepths(double[] depths)

Verifies that a set of depth values fall within range of DEPTH_MIN and DEPTH_MAX (inclusive).

Parameters:

depths - depths to validate

Throws:

IllegalArgumentException - if any depths value is out of range

See Also:

DataUtils.validate(double, double, double...)

validateDepth

public static void validateDepth(double depth)

Verifies that a depth value falls within range of DEPTH_MIN and DEPTH_MAX (inclusive).

Parameters:

depth - depth to validate

Throws:

IllegalArgumentException - if a depth value is out of range

See Also:

DataUtils.validate(double, double, double)

radiusAtLocation

public static double radiusAtLocation(Location p)

Returns the radius of the earth at the latitude of the supplied Location (see Wikipedia for source).

Parameters:

p - the Location at which to compute the earth's radius

Returns:

the earth's radius at the supplied Location

degreesLatPerKm

public static double degreesLatPerKm(Location p)

Returns the number of degrees of latitude per km at a given Location. This can be used to convert between km-based and degree-based grid spacing. The calculation takes into account the shape of the earth (oblate spheroid) and scales the conversion accordingly.

Parameters:

p - the Location at which to conversion value

Returns:

the number of decimal degrees latitude per km at a given Location

See Also:

radiusAtLocation(Location)

degreesLonPerKm

public static double degreesLonPerKm(Location p)

Returns the number of degrees of longitude per km at a given Location. This can be used to convert between km-based and degree-based grid spacing. The calculation scales the degrees longitude per km at the equator by the cosine of the supplied latitude. (Note: The values returned are not based on the radius of curvature of the earth at the supplied location.)

Parameters:

p - the Location at which to conversion value

Returns:

the number of decimal degrees longitude per km at a given Location

secondsToDeg

public static double secondsToDeg(double seconds)

Converts arcseconds to decimal degrees.

Parameters:

seconds - value to convert

Returns:

the equivalent number of decimal degrees

minutesToDeg

public static double minutesToDeg(double minutes)

Converts arcminutes to decimal degrees.

Parameters:

minutes - value to convert

Returns:

the equivalent number of decimal degrees

toDecimalDegrees

public static double toDecimalDegrees(double degrees,
                                      double minutes)

Converts 'degree : decimal minutes' to decimal degrees.

Parameters:

degrees - part to convert

minutes - part to convert (decimal minutes)

Returns:

converted value