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<?php
/**
* Author : Julien Moquet
*
* Inspired by Proj4php from Mike Adair madairATdmsolutions.ca
* and Richard Greenwood rich@greenwoodma$p->com
* License: LGPL as per: http://www.gnu.org/copyleft/lesser.html
*/
/* * *****************************************************************************
NAME OBLIQUE MERCATOR (HOTINE)
PURPOSE: Transforms input longitude and latitude to Easting and
Northing for the Oblique Mercator projection. The
longitude and latitude must be in radians. The Easting
and Northing values will be returned in meters.
PROGRAMMER DATE
---------- ----
T. Mittan Mar, 1993
ALGORITHM REFERENCES
1. Snyder, John P., "Map Projections--A Working Manual", U.S. Geological
Survey Professional Paper 1395 (Supersedes USGS Bulletin 1532), United
State Government Printing Office, Washington D.C., 1987.
2. Snyder, John P. and Voxland, Philip M., "An Album of Map Projections",
U.S. Geological Survey Professional Paper 1453 , United State Government
Printing Office, Washington D.C., 1989.
* ***************************************************************************** */
class Proj4phpProjOmerc {
/* Initialize the Oblique Mercator projection
------------------------------------------ */
public function init() {
if( !$this->mode )
$this->mode = 0;
if( !$this->lon1 ) {
$this->lon1 = 0;
$this->mode = 1;
}
if( !$this->lon2 )
$this->lon2 = 0;
if( !$this->lat2 )
$this->lat2 = 0;
/* Place parameters in static storage for common use
------------------------------------------------- */
$temp = $this->b / $this->a;
$es = 1.0 - pow( $temp, 2 );
$e = sqrt( $es );
$this->sin_p20 = sin( $this->lat0 );
$this->cos_p20 = cos( $this->lat0 );
$this->con = 1.0 - $this->es * $this->sin_p20 * $this->sin_p20;
$this->com = sqrt( 1.0 - $es );
$this->bl = sqrt( 1.0 + $this->es * pow( $this->cos_p20, 4.0 ) / (1.0 - $es) );
$this->al = $this->a * $this->bl * $this->k0 * $this->com / $this->con;
if( abs( $this->lat0 ) < Proj4php::$common->EPSLN ) {
$this->ts = 1.0;
$this->d = 1.0;
$this->el = 1.0;
} else {
$this->ts = Proj4php::$common->tsfnz( $this->e, $this->lat0, $this->sin_p20 );
$this->con = sqrt( $this->con );
$this->d = $this->bl * $this->com / ($this->cos_p20 * $this->con);
if( ($this->d * $this->d - 1.0) > 0.0 ) {
if( $this->lat0 >= 0.0 ) {
$this->f = $this->d + sqrt( $this->d * $this->d - 1.0 );
} else {
$this->f = $this->d - sqrt( $this->d * $this->d - 1.0 );
}
} else {
$this->f = $this->d;
}
$this->el = $this->f * pow( $this->ts, $this->bl );
}
//$this->longc=52.60353916666667;
if( $this->mode != 0 ) {
$this->g = .5 * ($this->f - 1.0 / $this->f);
$this->gama = Proj4php::$common->asinz( sin( $this->alpha ) / $this->d );
$this->longc = $this->longc - Proj4php::$common->asinz( $this->g * tan( $this->gama ) ) / $this->bl;
/* Report parameters common to format B
------------------------------------- */
//genrpt(azimuth * R2D,"Azimuth of Central Line: ");
//cenlon(lon_origin);
// cenlat(lat_origin);
$this->con = abs( $this->lat0 );
if( ($this->con > Proj4php::$common->EPSLN) && (abs( $this->con - Proj4php::$common->HALF_PI ) > Proj4php::$common->EPSLN) ) {
$this->singam = sin( $this->gama );
$this->cosgam = cos( $this->gama );
$this->sinaz = sin( $this->alpha );
$this->cosaz = cos( $this->alpha );
if( $this->lat0 >= 0 ) {
$this->u = ($this->al / $this->bl) * atan( sqrt( $this->d * $this->d - 1.0 ) / $this->cosaz );
} else {
$this->u = -($this->al / $this->bl) * atan( sqrt( $this->d * $this->d - 1.0 ) / $this->cosaz );
}
} else {
Proj4php::reportError( "omerc:Init:DataError" );
}
} else {
$this->sinphi = sin( $this->at1 );
$this->ts1 = Proj4php::$common->tsfnz( $this->e, $this->lat1, $this->sinphi );
$this->sinphi = sin( $this->lat2 );
$this->ts2 = Proj4php::$common->tsfnz( $this->e, $this->lat2, $this->sinphi );
$this->h = pow( $this->ts1, $this->bl );
$this->l = pow( $this->ts2, $this->bl );
$this->f = $this->el / $this->h;
$this->g = .5 * ($this->f - 1.0 / $this->f);
$this->j = ($this->el * $this->el - $this->l * $this->h) / ($this->el * $this->el + $this->l * $this->h);
$this->p = ($this->l - $this->h) / ($this->l + $this->h);
$this->dlon = $this->lon1 - $this->lon2;
if( $this->dlon < -Proj4php::$common->PI )
$this->lon2 = $this->lon2 - 2.0 * Proj4php::$common->PI;
if( $this->dlon > Proj4php::$common->PI )
$this->lon2 = $this->lon2 + 2.0 * Proj4php::$common->PI;
$this->dlon = $this->lon1 - $this->lon2;
$this->longc = .5 * ($this->lon1 + $this->lon2) - atan( $this->j * tan( .5 * $this->bl * $this->dlon ) / $this->p ) / $this->bl;
$this->dlon = Proj4php::$common->adjust_lon( $this->lon1 - $this->longc );
$this->gama = atan( sin( $this->bl * $this->dlon ) / $this->g );
$this->alpha = Proj4php::$common->asinz( $this->d * sin( $this->gama ) );
/* Report parameters common to format A
------------------------------------- */
if( abs( $this->lat1 - $this->lat2 ) <= Proj4php::$common->EPSLN ) {
Proj4php::reportError( "omercInitDataError" );
//return(202);
} else {
$this->con = abs( $this->lat1 );
}
if( ($this->con <= Proj4php::$common->EPSLN) || (abs( $this->con - Proj4php::$common->HALF_PI ) <= Proj4php::$common->EPSLN) ) {
Proj4php::reportError( "omercInitDataError" );
//return(202);
} else {
if( abs( abs( $this->lat0 ) - Proj4php::$common->HALF_PI ) <= Proj4php::$common->EPSLN ) {
Proj4php::reportError( "omercInitDataError" );
//return(202);
}
}
$this->singam = sin( $this->gam );
$this->cosgam = cos( $this->gam );
$this->sinaz = sin( $this->alpha );
$this->cosaz = cos( $this->alpha );
if( $this->lat0 >= 0 ) {
$this->u = ($this->al / $this->bl) * atan( sqrt( $this->d * $this->d - 1.0 ) / $this->cosaz );
} else {
$this->u = -($this->al / $this->bl) * atan( sqrt( $this->d * $this->d - 1.0 ) / $this->cosaz );
}
}
}
/* Oblique Mercator forward equations--mapping lat,long to x,y
---------------------------------------------------------- */
public function forward( $p ) {
/*
$theta; // angle
$sin_phi;
$cos_phi; // sin and cos value
$b; // temporary values
$c;
$t;
$tq; // temporary values
$con;
$n;
$ml; // cone constant, small m
$q;
$us;
$vl;
$ul;
$vs;
$s;
$dlon;
$ts1;
*/
$lon = $p->x;
$lat = $p->y;
/* Forward equations
----------------- */
$sin_phi = sin( $lat );
$dlon = Proj4php::$common->adjust_lon( $lon - $this->longc );
$vl = sin( $this->bl * $dlon );
if( abs( abs( $lat ) - Proj4php::$common->HALF_PI ) > Proj4php::$common->EPSLN ) {
$ts1 = Proj4php::$common->tsfnz( $this->e, $lat, $sin_phi );
$q = $this->el / (pow( $ts1, $this->bl ));
$s = .5 * ($q - 1.0 / $q);
$t = .5 * ($q + 1.0 / $q);
$ul = ($s * $this->singam - $vl * $this->cosgam) / $t;
$con = cos( $this->bl * $dlon );
if( abs( con ) < .0000001 ) {
$us = $this->al * $this->bl * $dlon;
} else {
$us = $this->al * atan( ($s * $this->cosgam + $vl * $this->singam) / $con ) / $this->bl;
if( $con < 0 )
$us = $us + Proj4php::$common->PI * $this->al / $this->bl;
}
} else {
if( $lat >= 0 ) {
$ul = $this->singam;
} else {
$ul = -$this->singam;
}
$us = $this->al * $lat / $this->bl;
}
if( abs( abs( $ul ) - 1.0 ) <= Proj4php::$common->EPSLN ) {
//alert("Point projects into infinity","omer-for");
Proj4php::reportError( "omercFwdInfinity" );
//return(205);
}
$vs = .5 * $this->al * log( (1.0 - $ul) / (1.0 + $ul) ) / $this->bl;
$us = $us - $this->u;
$p->x = $this->x0 + $vs * $this->cosaz + $us * $this->sinaz;
$p->y = $this->y0 + $us * $this->cosaz - $vs * $this->sinaz;
return $p;
}
/**
*
* @param type $p
* @return type
*/
public function inverse( $p ) {
/*
$delta_lon; /* Delta longitude (Given longitude - center
$theta; /* angle
$delta_theta; /* adjusted longitude
$sin_phi;
$cos_phi; /* sin and cos value
$b; /* temporary values
$c;
$t;
$tq; /* temporary values
$con;
$n;
$ml; /* cone constant, small m
$vs;
$us;
$q;
$s;
$ts1;
$vl;
$ul;
$bs;
$dlon;
$flag;
*/
/* Inverse equations
----------------- */
$p->x -= $this->x0;
$p->y -= $this->y0;
#$flag = 0;
$vs = $p->x * $this->cosaz - $p->y * $this->sinaz;
$us = $p->y * $this->cosaz + $p->x * $this->sinaz;
$us = $us + $this->u;
$q = exp( -$this->bl * $vs / $this->al );
$s = .5 * ($q - 1.0 / $q);
$t = .5 * ($q + 1.0 / $q);
$vl = sin( $this->bl * $us / $this->al );
$ul = ($vl * $this->cosgam + $s * $this->singam) / $t;
if( abs( abs( $ul ) - 1.0 ) <= Proj4php::$common->EPSLN ) {
$lon = $this->longc;
if( ul >= 0.0 ) {
$lat = Proj4php::$common->HALF_PI;
} else {
$lat = -Proj4php::$common->HALF_PI;
}
} else {
$con = 1.0 / $this->bl;
$ts1 = pow( ($this->el / sqrt( (1.0 + $ul) / (1.0 - $ul) ) ), $con );
$lat = Proj4php::$common->phi2z( $this->e, $ts1 );
//if ($flag != 0)
//return($flag);
//~ con = cos($this->bl * us /al);
$theta = $this->longc - atan2( ($s * $this->cosgam - $vl * $this->singam ), $con ) / $this->bl;
$lon = Proj4php::$common->adjust_lon( $theta );
}
$p->x = $lon;
$p->y = $lat;
return $p;
}
}
Proj4php::$proj['omerc'] = new Proj4phpProjOmerc();