/*
Copyright 2006 Jerry Huxtable
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/*
* This file was semi-automatically converted from the public-domain USGS PROJ source.
*/
package com.jhlabs.map.proj;
import java.awt.*;
import java.awt.geom.*;
import com.jhlabs.map.*;
public class EqualAreaAzimuthalProjection extends AzimuthalProjection {
private double sinb1;
private double cosb1;
private double xmf;
private double ymf;
private double mmf;
private double qp;
private double dd;
private double rq;
private double[] apa;
public EqualAreaAzimuthalProjection() {
initialize();
}
public Object clone() {
EqualAreaAzimuthalProjection p = (EqualAreaAzimuthalProjection)super.clone();
if (apa != null)
p.apa = (double[])apa.clone();
return p;
}
public void initialize() {
super.initialize();
if (spherical) {
if (mode == OBLIQUE) {
sinphi0 = Math.sin(projectionLatitude);
cosphi0 = Math.cos(projectionLatitude);
}
} else {
double sinphi;
qp = MapMath.qsfn(1., e, one_es);
mmf = .5 / (1. - es);
apa = MapMath.authset(es);
switch (mode) {
case NORTH_POLE:
case SOUTH_POLE:
dd = 1.;
break;
case EQUATOR:
dd = 1. / (rq = Math.sqrt(.5 * qp));
xmf = 1.;
ymf = .5 * qp;
break;
case OBLIQUE:
rq = Math.sqrt(.5 * qp);
sinphi = Math.sin(projectionLatitude);
sinb1 = MapMath.qsfn(sinphi, e, one_es) / qp;
cosb1 = Math.sqrt(1. - sinb1 * sinb1);
dd = Math.cos(projectionLatitude) / (Math.sqrt(1. - es * sinphi * sinphi) *
rq * cosb1);
ymf = (xmf = rq) / dd;
xmf *= dd;
break;
}
}
}
public Point2D.Double project(double lam, double phi, Point2D.Double xy) {
if (spherical) {
double coslam, cosphi, sinphi;
sinphi = Math.sin(phi);
cosphi = Math.cos(phi);
coslam = Math.cos(lam);
switch (mode) {
case EQUATOR:
xy.y = 1. + cosphi * coslam;
if (xy.y <= EPS10) throw new ProjectionException();
xy.x = (xy.y = Math.sqrt(2. / xy.y)) * cosphi * Math.sin(lam);
xy.y *= mode == EQUATOR ? sinphi :
cosphi0 * sinphi - sinphi0 * cosphi * coslam;
break;
case OBLIQUE:
xy.y = 1. + sinphi0 * sinphi + cosphi0 * cosphi * coslam;
if (xy.y <= EPS10) throw new ProjectionException();
xy.x = (xy.y = Math.sqrt(2. / xy.y)) * cosphi * Math.sin(lam);
xy.y *= mode == EQUATOR ? sinphi :
cosphi0 * sinphi - sinphi0 * cosphi * coslam;
break;
case NORTH_POLE:
coslam = -coslam;
case SOUTH_POLE:
if (Math.abs(phi + projectionLatitude) < EPS10) throw new ProjectionException();
xy.y = MapMath.QUARTERPI - phi * .5;
xy.y = 2. * (mode == SOUTH_POLE ? Math.cos(xy.y) : Math.sin(xy.y));
xy.x = xy.y * Math.sin(lam);
xy.y *= coslam;
break;
}
} else {
double coslam, sinlam, sinphi, q, sinb = 0, cosb = 0, b = 0;
coslam = Math.cos(lam);
sinlam = Math.sin(lam);
sinphi = Math.sin(phi);
q = MapMath.qsfn(sinphi, e, one_es);
if (mode == OBLIQUE || mode == EQUATOR) {
sinb = q / qp;
cosb = Math.sqrt(1. - sinb * sinb);
}
switch (mode) {
case OBLIQUE:
b = 1. + sinb1 * sinb + cosb1 * cosb * coslam;
break;
case EQUATOR:
b = 1. + cosb * coslam;
break;
case NORTH_POLE:
b = MapMath.HALFPI + phi;
q = qp - q;
break;
case SOUTH_POLE:
b = phi - MapMath.HALFPI;
q = qp + q;
break;
}
if (Math.abs(b) < EPS10) throw new ProjectionException();
switch (mode) {
case OBLIQUE:
xy.y = ymf * ( b = Math.sqrt(2. / b) )
* (cosb1 * sinb - sinb1 * cosb * coslam);
xy.x = xmf * b * cosb * sinlam;
break;
case EQUATOR:
xy.y = (b = Math.sqrt(2. / (1. + cosb * coslam))) * sinb * ymf;
xy.x = xmf * b * cosb * sinlam;
break;
case NORTH_POLE:
case SOUTH_POLE:
if (q >= 0.) {
xy.x = (b = Math.sqrt(q)) * sinlam;
xy.y = coslam * (mode == SOUTH_POLE ? b : -b);
} else
xy.x = xy.y = 0.;
break;
}
}
return xy;
}
public Point2D.Double projectInverse(double x, double y, Point2D.Double lp) {
if (spherical) {
double cosz = 0, rh, sinz = 0;
rh = MapMath.distance(x, y);
if ((lp.y = rh * .5 ) > 1.) throw new ProjectionException();
lp.y = 2. * Math.asin(lp.y);
if (mode == OBLIQUE || mode == EQUATOR) {
sinz = Math.sin(lp.y);
cosz = Math.cos(lp.y);
}
switch (mode) {
case EQUATOR:
lp.y = Math.abs(rh) <= EPS10 ? 0. : Math.asin(y * sinz / rh);
x *= sinz;
y = cosz * rh;
break;
case OBLIQUE:
lp.y = Math.abs(rh) <= EPS10 ? projectionLatitude :
Math.asin(cosz * sinphi0 + y * sinz * cosphi0 / rh);
x *= sinz * cosphi0;
y = (cosz - Math.sin(lp.y) * sinphi0) * rh;
break;
case NORTH_POLE:
y = -y;
lp.y = MapMath.HALFPI - lp.y;
break;
case SOUTH_POLE:
lp.y -= MapMath.HALFPI;
break;
}
lp.x = (y == 0. && (mode == EQUATOR || mode == OBLIQUE)) ?
0. : Math.atan2(x, y);
} else {
double cCe, sCe, q, rho, ab = 0;
switch (mode) {
case EQUATOR:
case OBLIQUE:
if ((rho = MapMath.distance(x /= dd, y *= dd)) < EPS10) {
lp.x = 0.;
lp.y = projectionLatitude;
return (lp);
}
cCe = Math.cos(sCe = 2. * Math.asin(.5 * rho / rq));
x *= (sCe = Math.sin(sCe));
if (mode == OBLIQUE) {
q = qp * (ab = cCe * sinb1 + y * sCe * cosb1 / rho);
y = rho * cosb1 * cCe - y * sinb1 * sCe;
} else {
q = qp * (ab = y * sCe / rho);
y = rho * cCe;
}
break;
case NORTH_POLE:
y = -y;
case SOUTH_POLE:
if ((q = (x * x + y * y)) == 0) {
lp.x = 0.;
lp.y = projectionLatitude;
return lp;
}
ab = 1. - q / qp;
if (mode == SOUTH_POLE)
ab = - ab;
break;
}
lp.x = Math.atan2(x, y);
lp.y = MapMath.authlat(Math.asin(ab), apa);
}
return lp;
}
public Shape getBoundingShape() {
double r = 1.414 * a;
return new Ellipse2D.Double( -r, -r, 2*r, 2*r );
}
/**
* Returns true if this projection is equal area
*/
public boolean isEqualArea() {
return true;
}
public boolean hasInverse() {
return true;
}
public String toString() {
return "Lambert Equal Area Azimuthal";
}
}