// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.data.projection.proj;
import static java.lang.Math.PI;
import static java.lang.Math.abs;
import static java.lang.Math.atan;
import static java.lang.Math.cos;
import static java.lang.Math.exp;
import static java.lang.Math.log;
import static java.lang.Math.pow;
import static java.lang.Math.sin;
import static java.lang.Math.sqrt;
import static java.lang.Math.tan;
import static java.lang.Math.toRadians;
import static org.openstreetmap.josm.tools.I18n.tr;
import org.openstreetmap.josm.data.projection.Ellipsoid;
import org.openstreetmap.josm.data.projection.ProjectionConfigurationException;
/**
* Implementation of the Lambert Conformal Conic projection.
*
* @author Pieren
*/
public class LambertConformalConic implements Proj {
protected Ellipsoid ellps;
protected double e;
public abstract static class Parameters {
public final double latitudeOrigin;
public Parameters(double latitudeOrigin) {
this.latitudeOrigin = latitudeOrigin;
}
}
public static class Parameters1SP extends Parameters {
public Parameters1SP(double latitudeOrigin) {
super(latitudeOrigin);
}
}
public static class Parameters2SP extends Parameters {
public final double standardParallel1;
public final double standardParallel2;
public Parameters2SP(double latitudeOrigin, double standardParallel1, double standardParallel2) {
super(latitudeOrigin);
this.standardParallel1 = standardParallel1;
this.standardParallel2 = standardParallel2;
}
}
private Parameters params;
/**
* projection exponent
*/
protected double n;
/**
* projection factor
*/
protected double F;
/**
* radius of the parallel of latitude of the false origin (2SP) or at
* natural origin (1SP)
*/
protected double r0;
/**
* precision in iterative schema
*/
protected static final double epsilon = 1e-12;
@Override
public void initialize(ProjParameters params) throws ProjectionConfigurationException {
ellps = params.ellps;
e = ellps.e;
if (params.lat_0 == null)
throw new ProjectionConfigurationException(tr("Parameter ''{0}'' required.", "lat_0"));
if (params.lat_1 != null && params.lat_2 != null) {
initialize2SP(params.lat_0, params.lat_1, params.lat_2);
} else {
initialize1SP(params.lat_0);
}
}
/**
* Initialize for LCC with 2 standard parallels.
*
* @param lat_0 latitude of false origin (in degrees)
* @param lat_1 latitude of first standard parallel (in degrees)
* @param lat_2 latitude of second standard parallel (in degrees)
*/
private void initialize2SP(double lat_0, double lat_1, double lat_2) {
this.params = new Parameters2SP(lat_0, lat_1, lat_2);
final double m1 = m(toRadians(lat_1));
final double m2 = m(toRadians(lat_2));
final double t1 = t(toRadians(lat_1));
final double t2 = t(toRadians(lat_2));
final double tf = t(toRadians(lat_0));
n = (log(m1) - log(m2)) / (log(t1) - log(t2));
F = m1 / (n * pow(t1, n));
r0 = F * pow(tf, n);
}
/**
* Initialize for LCC with 1 standard parallel.
*
* @param lat_0 latitude of natural origin (in degrees)
*/
private void initialize1SP(double lat_0) {
this.params = new Parameters1SP(lat_0);
final double lat_0_rad = toRadians(lat_0);
final double m0 = m(lat_0_rad);
final double t0 = t(lat_0_rad);
n = sin(lat_0_rad);
F = m0 / (n * pow(t0, n));
r0 = F * pow(t0, n);
}
/**
* auxiliary function t
*/
protected double t(double lat_rad) {
return tan(PI/4 - lat_rad / 2.0)
/ pow(( (1.0 - e * sin(lat_rad)) / (1.0 + e * sin(lat_rad))) , e/2);
}
/**
* auxiliary function m
*/
protected double m(double lat_rad) {
return cos(lat_rad) / (sqrt(1 - e * e * pow(sin(lat_rad), 2)));
}
@Override
public String getName() {
return tr("Lambert Conformal Conic");
}
@Override
public String getProj4Id() {
return "lcc";
}
@Override
public double[] project(double phi, double lambda) {
double sinphi = sin(phi);
double L = (0.5*log((1+sinphi)/(1-sinphi))) - e/2*log((1+e*sinphi)/(1-e*sinphi));
double r = F*exp(-n*L);
double gamma = n*lambda;
double X = r*sin(gamma);
double Y = r0 - r*cos(gamma);
return new double[] { X, Y };
}
@Override
public double[] invproject(double east, double north) {
double r = sqrt(pow(east,2) + pow(north-r0, 2));
double gamma = atan(east / (r0-north));
double lambda = gamma/n;
double latIso = (-1/n) * log(abs(r/F));
double phi = ellps.latitude(latIso, e, epsilon);
return new double[] { phi, lambda };
}
public final Parameters getParameters() {
return params;
}
}