/**
* Albers Conical Equal Area forward equations--mapping lat,long to x,y
*
* @param Point $p
* @return Point $p
*/
public function forward($p)
{
$lon = $p->x;
$lat = $p->y;
$this->sin_phi = sin($lat);
$this->cos_phi = cos($lat);
$qs = Common::qsfnz($this->e3, $this->sin_phi, $this->cos_phi);
$rh1 = $this->a * sqrt($this->c - $this->ns0 * $qs) / $this->ns0;
$theta = $this->ns0 * Common::adjust_lon($lon - $this->long0);
$x = rh1 * sin($theta) + $this->x0;
$y = $this->rh - $rh1 * cos($theta) + $this->y0;
$p->x = $x;
$p->y = $y;
return $p;
}
public function forward($p)
{
/* Forward equations
----------------- */
#$x;
#$y;
$lam = $p->x;
$phi = $p->y;
$lam = Common::adjust_lon($lam - $this->long0);
if ($this->sphere) {
/*
$coslam;
$cosphi;
$sinphi;
*/
$sinphi = sin($phi);
$cosphi = cos($phi);
$coslam = cos($lam);
switch ($this->mode) {
case $this->OBLIQ:
case $this->EQUIT:
$y = $this->mode == $this->EQUIT ? 1.0 + $cosphi * $coslam : 1.0 + $this->sinph0 * $sinphi + $this->cosph0 * $cosphi * $coslam;
if (y <= Common::EPSLN) {
Proj4php::reportError("laea:fwd:y less than eps");
return null;
}
$y = sqrt(2.0 / $y);
$x = $y * cosphi * sin($lam);
$y *= $this->mode == $this->EQUIT ? $sinphi : $this->cosph0 * $sinphi - $this->sinph0 * $cosphi * $coslam;
break;
case $this->N_POLE:
$coslam = -$coslam;
case $this->S_POLE:
if (abs($phi + $this->phi0) < Common::EPSLN) {
Proj4php::reportError("laea:fwd:phi < eps");
return;
}
$y = Common::FORTPI - $phi * 0.5;
$y = 2.0 * ($this->mode == $this->S_POLE ? cos($y) : sin($y));
$x = $y * sin($lam);
$y *= $coslam;
break;
}
} else {
/*
$coslam;
$sinlam;
$sinphi;
$q;
*/
$sinb = 0.0;
$cosb = 0.0;
$b = 0.0;
$coslam = cos($lam);
$sinlam = sin($lam);
$sinphi = sin($phi);
$q = Common::qsfnz($this->e, $sinphi);
if ($this->mode == $this->OBLIQ || $this->mode == $this->EQUIT) {
$sinb = $q / $this->qp;
$cosb = sqrt(1.0 - $sinb * $sinb);
}
switch ($this->mode) {
case $this->OBLIQ:
$b = 1.0 + $this->sinb1 * $sinb + $this->cosb1 * $cosb * $coslam;
break;
case $this->EQUIT:
$b = 1.0 + $cosb * $coslam;
break;
case $this->N_POLE:
$b = Common::HALF_PI + $phi;
$q = $this->qp - $q;
break;
case $this->S_POLE:
$b = $phi - Common::HALF_PI;
$q = $this->qp + $q;
break;
}
if (abs($b) < Common::EPSLN) {
Proj4php::reportError("laea:fwd:b < eps");
return null;
}
switch ($this->mode) {
case $this->OBLIQ:
case $this->EQUIT:
$b = sqrt(2.0 / $b);
if ($this->mode == $this->OBLIQ) {
$y = $this->ymf * $b * ($this->cosb1 * $sinb - $this->sinb1 * $cosb * $coslam);
} else {
$y = ($b = sqrt(2.0 / (1.0 + $cosb * $coslam))) * $sinb * $this->ymf;
}
$x = $this->xmf * $b * $cosb * $sinlam;
break;
case $this->N_POLE:
case $this->S_POLE:
if (q >= 0.0) {
$x = ($b = sqrt($q)) * $sinlam;
$y = $coslam * ($this->mode == $this->S_POLE ? $b : -$b);
} else {
$x = $y = 0.0;
}
break;
}
}
//v 1.0
/*
$sin_lat=sin(lat);
$cos_lat=cos(lat);
$sin_delta_lon=sin(delta_lon);
$cos_delta_lon=cos(delta_lon);
$g =$this->sin_lat_o * sin_lat +$this->cos_lat_o * cos_lat * cos_delta_lon;
if (g == -1.0) {
Proj4php::reportError("laea:fwd:Point projects to a circle of radius "+ 2.0 * R);
return null;
}
$ksp = $this->a * sqrt(2.0 / (1.0 + g));
$x = ksp * cos_lat * sin_delta_lon + $this->x0;
$y = ksp * ($this->cos_lat_o * sin_lat - $this->sin_lat_o * cos_lat * cos_delta_lon) + $this->y0;
*/
$p->x = $this->a * $x + $this->x0;
$p->y = $this->a * $y + $this->y0;
return $p;
}
