67 lines
1.6 KiB
Java
67 lines
1.6 KiB
Java
|
/*
|
||
|
|
* Mercator.java 2004-11-29
|
||
|
|
*
|
||
|
|
* Thomas Behr, FernUniversitaet Hagen
|
||
|
|
* adapted by Dirk Ansorge, FernUniversitaet Hagen
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
package twodsack.io;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This class provides methods for coordinate transformation. Of the huge amount of different
|
||
|
|
* transformations for geographical data, this class provides methods for the Mercator transformation.
|
||
|
|
*/
|
||
|
|
public class Mercator {
|
||
|
|
/*
|
||
|
|
* constructors
|
||
|
|
*/
|
||
|
|
/**
|
||
|
|
* Don't use this constructor.
|
||
|
|
*/
|
||
|
|
private Mercator(){}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* fields
|
||
|
|
*/
|
||
|
|
static final double LOG_E = Math.log(Math.E);
|
||
|
|
static final double PI = Math.PI;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* methods
|
||
|
|
*/
|
||
|
|
/**
|
||
|
|
* Computes the projection of the <tt>x</tt> coordinate.
|
||
|
|
*
|
||
|
|
* @param lambda lambda value
|
||
|
|
* @param phi phi value
|
||
|
|
*/
|
||
|
|
public static double getPrjX(double lambda, double phi) {
|
||
|
|
return lambda-Lambda_0;
|
||
|
|
}//end method getPrjX
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Computes the projection of the <tt>y</tt> coordinate.
|
||
|
|
*
|
||
|
|
* @param lambda lambda value
|
||
|
|
* @param phi phi value
|
||
|
|
*/
|
||
|
|
public static double getPrjY(double lambda, double phi) throws InvalidInputException{
|
||
|
|
if(phi>90 || phi<-90)
|
||
|
|
throw new InvalidInputException("phi out of range");
|
||
|
|
if( phi<=(-90+secure_distance))
|
||
|
|
phi = -90+secure_distance;
|
||
|
|
if( phi>=(90-secure_distance))
|
||
|
|
phi = 90-secure_distance;
|
||
|
|
|
||
|
|
double phi_2 = phi*PI/180;
|
||
|
|
double y = Math.log(Math.tan(PI/4 + phi_2/2))/LOG_E;
|
||
|
|
return y*180/PI;
|
||
|
|
}//end method getPrjY
|
||
|
|
|
||
|
|
private static double Lambda_0 = 0;
|
||
|
|
private static double secure_distance = 1;
|
||
|
|
|
||
|
|
}//end class Mercator
|