com.bigdata.rdf.internal.gis

Class CoordinateUtility

java.lang.Object

com.bigdata.rdf.internal.gis.CoordinateUtility

public class CoordinateUtility
extends Object

Utility class for operations on ICoordinates.

Version:

$Id$

Author:

Bryan Thompson

See Also:

http://en.wikipedia.org/wiki/Geographic_coordinate_system, http://en.wikipedia.org/wiki/Earth_radius, http://barelybad.com/north_of_canada_map.htm

Field Summary

Fields

Modifier and Type	Field and Description
static double	metersPerDegreeOfLatitudeAtSeaLevel The #of meters per degree of latitude at sea level (this is the same regardless of the degrees north/south).
static double	metersPerMinuteOfLatitudeAtSeaLevel The #of meters per minute of latitude at sea level (this is the same regardless of the degrees north/south).
static double	metersPerSecondOfLatitudeAtSeaLevel The #of meters per second of latitude at sea level 30.82 (this is the same regardless of the degrees north/south).
static double	metersPerSecondOfLongitudeAtSeaLevelAtEquator The #of meters per second of longitude at sea level on the equator.

Constructor Summary

Constructors

Constructor and Description
CoordinateUtility()

Method Summary

Methods

Modifier and Type	Method and Description
static double	approxMetersPerDegreeOfLongitudeAtSeaLevel(double degreesNorth) The approximate width of a longitudinal degree on a given latitude.
static void	assertDegreeLatitude(double d)
static void	assertDegreeLongitude(double d)
static CoordinateDD	boundingBoxNorthEast(CoordinateDD start, double distance, ICoordinate.UNITS units)
static CoordinateDD	boundingBoxSouthWest(CoordinateDD start, double distance, ICoordinate.UNITS units)
static double	distance(CoordinateDD p1, CoordinateDD p2, ICoordinate.UNITS units) Computes the distance between two coordinates.
static double	distanceInMeters(double latP1, double latP2, double lonP1, double lonP2) Computes the distance between two coordinates in meters.
static double	metersToUnits(double meters, ICoordinate.UNITS units) Convert meters to the desired units.
static double	realMetersPerDegreeOfLongitudeAtSeaLevel(double degreesNorth) The real width of a longitudinal degree on a given latitude (this accounts for the flattening of the Earth).
static double	toDecimalDegrees(int degrees, int minutes, double seconds) Convert Degrees, Minutes, and Seconds to Decimal Degrees.
static double	toDegrees(double radians) Convert radians to degrees.
static double	toRadians(double degrees) Convert degrees to radians.
static double	unitsToMeters(double val, ICoordinate.UNITS units) Convert meters to the desired units.

Methods inherited from class java.lang.Object

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

Field Detail

metersPerSecondOfLatitudeAtSeaLevel

public static double metersPerSecondOfLatitudeAtSeaLevel

The #of meters per second of latitude at sea level 30.82 (this is the same regardless of the degrees north/south).

metersPerMinuteOfLatitudeAtSeaLevel

public static double metersPerMinuteOfLatitudeAtSeaLevel

The #of meters per minute of latitude at sea level (this is the same regardless of the degrees north/south).

metersPerDegreeOfLatitudeAtSeaLevel

public static double metersPerDegreeOfLatitudeAtSeaLevel

The #of meters per degree of latitude at sea level (this is the same regardless of the degrees north/south).

metersPerSecondOfLongitudeAtSeaLevelAtEquator

public static double metersPerSecondOfLongitudeAtSeaLevelAtEquator

The #of meters per second of longitude at sea level on the equator. The #of meters per second of longitude decreases as the angle increases until it becomes zero (0) at the poles (at the poles the longitudinal radius of a sphere is always zero).

Constructor Detail

CoordinateUtility

public CoordinateUtility()

Method Detail

realMetersPerDegreeOfLongitudeAtSeaLevel

public static double realMetersPerDegreeOfLongitudeAtSeaLevel(double degreesNorth)

The real width of a longitudinal degree on a given latitude (this accounts for the flattening of the Earth).

Parameters:

degreesNorth - The latitude (north/south).

Returns:

The real width of a degree of longitude at sea level at the given latitude.

See Also:

approxMetersPerDegreeOfLongitudeAtSeaLevel(double)

boundingBoxSouthWest

public static CoordinateDD boundingBoxSouthWest(CoordinateDD start,
                                double distance,
                                ICoordinate.UNITS units)

boundingBoxNorthEast

public static CoordinateDD boundingBoxNorthEast(CoordinateDD start,
                                double distance,
                                ICoordinate.UNITS units)

assertDegreeLatitude

public static void assertDegreeLatitude(double d)

assertDegreeLongitude

public static void assertDegreeLongitude(double d)

approxMetersPerDegreeOfLongitudeAtSeaLevel

public static double approxMetersPerDegreeOfLongitudeAtSeaLevel(double degreesNorth)

The approximate width of a longitudinal degree on a given latitude.

Note: This routine is faster than realMetersPerDegreeOfLongitudeAtSeaLevel(double) but does not account for the flattening of the Earth.

Parameters:

degreesNorth - The latitude (north/south).

Returns:

The approximate width of a longitudial degree at that latitude.

See Also:

realMetersPerDegreeOfLongitudeAtSeaLevel(double)

toRadians

public static double toRadians(double degrees)

Convert degrees to radians.

Parameters:

degrees - The angle in degrees.

Returns:

The angle in radians.

toDegrees

public static double toDegrees(double radians)

Convert radians to degrees.

Parameters:

radians - The angle in radians.

Returns:

The angle in degrees.

distance

public static double distance(CoordinateDD p1,
              CoordinateDD p2,
              ICoordinate.UNITS units)

Computes the distance between two coordinates.

Parameters:

p1 - coordinate one

p2 - coordinate two

units - desired return unit

Returns:

distanceInMeters

public static double distanceInMeters(double latP1,
                      double latP2,
                      double lonP1,
                      double lonP2)

Computes the distance between two coordinates in meters.

Parameters:

latP1 - latitude of point #1

latP2 - latitude of point #2

lonP1 - latitude of point #1

lonP1 - latitude of point #2

units - desired return unit

Returns:

metersToUnits

public static double metersToUnits(double meters,
                   ICoordinate.UNITS units)

Convert meters to the desired units.

Parameters:

meters - The #of meters.

units - The target units.

Returns:

The converted distance.

unitsToMeters

public static double unitsToMeters(double val,
                   ICoordinate.UNITS units)

Convert meters to the desired units.

Parameters:

meters - The #of meters.

units - The target units.

Returns:

The converted distance.

toDecimalDegrees

public static double toDecimalDegrees(int degrees,
                      int minutes,
                      double seconds)

Convert Degrees, Minutes, and Seconds to Decimal Degrees.

Parameters:

degrees - Degrees

minutes - Minutes (w/ fraction).

seconds - Seconds (w/ fractial seconds).

Returns:

The angle in decimal degrees.