de.topobyte.geomath

Class WGS84

java.lang.Object

de.topobyte.geomath.WGS84

public class WGS84
extends Object

This class provides methods for calculations with the WGS84 projection. It offers conversions between WGS84 coordinates and the plane used in Mercator-projection. It also contains a method for calculating the distance between two coordinates using the haversine formula.

Constructor Summary

Constructors

Constructor and Description
WGS84()

Method Summary

Modifier and Type	Method and Description
static double	haversineDistance(double lon1, double lat1, double lon2, double lat2) Calculate the distance in meters from (lon1, lat1) to (lon2, lat2) using the haversine formula and a mean earth radius of 6371008.67 meters.
static double	lat2merc(double lat) The inverse of merc2lat.
static double	lat2merc(double lat, double worldsize) The inverse of merc2lat.
static double	lon2merc(double lon) The inverse of merc2lon.
static double	lon2merc(double lon, double worldsize) The inverse of merc2lon.
static double	merc2lat(double y) Convert a position on the unit plane to a longitude.
static double	merc2lat(double y, double worldsize) Convert a position on the plane to a longitude.
static double	merc2lon(double x) Convert a position on the unit plane to a longitude.
static double	merc2lon(double x, double worldsize) Convert a position on the plane to a longitude.

Methods inherited from class java.lang.Object

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

Constructor Detail

WGS84

public WGS84()

Method Detail

merc2lon

public static double merc2lon(double x)

Convert a position on the unit plane to a longitude.

Parameters:

x - the position on the plane (interval is [0..1]).

Returns:

the longitude.

merc2lon

public static double merc2lon(double x,
                              double worldsize)

Convert a position on the plane to a longitude.

Parameters:

x - the position on the plane (interval is [0..worldsize]).

worldsize - a bound used to calculate the relative position of x on the Mercator-plane.

Returns:

the longitude.

merc2lat

public static double merc2lat(double y)

Convert a position on the unit plane to a longitude.

Parameters:

y - the position on the plane (interval is [0..1]).

Returns:

the latitude.

merc2lat

public static double merc2lat(double y,
                              double worldsize)

Convert a position on the plane to a longitude.

Parameters:

y - the position on the plane (interval is [0..worldsize]).

worldsize - a bound used to calculate the relative position of y on the Mercator-plane.

Returns:

the latitude.

lon2merc

public static double lon2merc(double lon)

The inverse of merc2lon.

Parameters:

lon - the longitude to convert.

Returns:

the relative position on the unit plane (interval [0..1] ).

lon2merc

public static double lon2merc(double lon,
                              double worldsize)

The inverse of merc2lon.

Parameters:

lon - the longitude to convert.

worldsize - the size of the Mercator-plane used to calculate the relative position x.

Returns:

the relative position on the plane (interval [0..worldsize]).

lat2merc

public static double lat2merc(double lat)

The inverse of merc2lat.

Parameters:

lat - the latitude to convert.

Returns:

the relative position on the unit plane (interval [0..1] ).

lat2merc

public static double lat2merc(double lat,
                              double worldsize)

The inverse of merc2lat.

Parameters:

lat - the latitude to convert.

worldsize - the size of the Mercator-plane used to calculate the relative position x.

Returns:

the relative position on the plane (interval [0..worldsize]).

haversineDistance

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

Calculate the distance in meters from (lon1, lat1) to (lon2, lat2) using the haversine formula and a mean earth radius of 6371008.67 meters.

Parameters:

lon1 - the first longitude.

lat1 - the first latitude.

lon2 - the second longitude.

lat2 - the second latitude.

Returns:

the distance between the two points in meters.