Subversion Repositories eFlore/Projets.eflore-projets

<?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 
 */
class Proj4phpProjSterea {

    protected $dependsOn = 'gauss';
    
    /**
     *
     * @return void 
     */
    public function init() {
        
        if( !$this->rc ) {
            Proj4php::reportError( "sterea:init:E_ERROR_0" );
            return;
        }
        
        $this->sinc0 = sin( $this->phic0 );
        $this->cosc0 = cos( $this->phic0 );
        $this->R2 = 2.0 * $this->rc;
        
        if( !$this->title )
            $this->title = "Oblique Stereographic Alternative";
    }

    /**
     *
     * @param type $p
     * @return type 
     */
    public function forward( $p ) {
        
        $p->x = Proj4php::$common->adjust_lon( $p->x - $this->long0 ); /* adjust del longitude */
        $p = Proj4php::$proj['gauss']->forward( $p );
        $sinc = sin( $p->y );
        $cosc = cos( $p->y );
        $cosl = cos( $p->x );
        $k = $this->k0 * $this->R2 / (1.0 + $this->sinc0 * $sinc + $this->cosc0 * $cosc * $cosl);
        
        $p->x = $k * $cosc * sin( $p->x );
        $p->y = $k * ($this->cosc0 * sinc - $this->sinc0 * $cosc * $cosl);
        
        $p->x = $this->a * $p->x + $this->x0;
        $p->y = $this->a * $p->y + $this->y0;
        
        return $p;
    }

    /**
     *
     * @param type $p
     * @return type 
     */
    public function inverse( $p ) {
        
        #$lon;
        #$lat;
        $p->x = ($p->x - $this->x0) / $this->a; /* descale and de-offset */
        $p->y = ($p->y - $this->y0) / $this->a;

        $p->x /= $this->k0;
        $p->y /= $this->k0;
        
        if( ($rho = sqrt( $p->x * $p->x + $p->y * $p->y ) ) ) {
            $c = 2.0 * atan2( $rho, $this->R2 );
            $sinc = sin( $c );
            $cosc = cos( $c );
            $lat = asin( $cosc * $this->sinc0 + $p->y * $sinc * $this->cosc0 / $rho );
            $lon = atan2( $p->x * $sinc, $rho * $this->cosc0 * $cosc - $p->y * $this->sinc0 * $sinc );
        } else {
            $lat = $this->phic0;
            $lon = 0.;
        }

        $p->x = $lon;
        $p->y = $lat;
        $p = Proj4php::$proj['gauss']->inverse( $p );
        $p->x = Proj4php::$common->adjust_lon( $p->x + $this->long0 ); /* adjust longitude to CM */
        
        return $p;
    }

}

Proj4php::$proj['sterea'] = new Proj4phpProjSterea();