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delphine |
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<?php
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/**
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* Author : Julien Moquet
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*
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* Inspired by Proj4php from Mike Adair madairATdmsolutions.ca
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* and Richard Greenwood rich@greenwoodma$p->com
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* License: LGPL as per: http://www.gnu.org/copyleft/lesser.html
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*/
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/*******************************************************************************
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NAME EQUIRECTANGULAR
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PURPOSE: Transforms input longitude and latitude to Easting and
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Northing for the Equirectangular projection. The
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longitude and latitude must be in radians. The Easting
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and Northing values will be returned in meters.
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PROGRAMMER DATE
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---------- ----
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T. Mittan Mar, 1993
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ALGORITHM REFERENCES
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1. Snyder, John P., "Map Projections--A Working Manual", U.S. Geological
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Survey Professional Paper 1395 (Supersedes USGS Bulletin 1532), United
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State Government Printing Office, Washington D.C., 1987.
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2. Snyder, John P. and Voxland, Philip M., "An Album of Map Projections",
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U.S. Geological Survey Professional Paper 1453 , United State Government
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Printing Office, Washington D.C., 1989.
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*******************************************************************************/
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class Proj4phpProjEqui {
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public function init() {
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if( !$this->x0 )
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$this->x0 = 0;
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if( !$this->y0 )
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$this->y0 = 0;
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if( !$this->lat0 )
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$this->lat0 = 0;
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if( !$this->long0 )
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$this->long0 = 0;
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///$this->t2;
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}
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/* Equirectangular forward equations--mapping lat,long to x,y
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--------------------------------------------------------- */
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public function forward( $p ) {
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$lon = $p->x;
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$lat = $p->y;
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$dlon = Proj4php::$common->adjust_lon( $lon - $this->long0 );
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$x = $this->x0 + $this->a * $dlon * cos( $this->lat0 );
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$y = $this->y0 + $this->a * $lat;
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$this->t1 = $x;
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$this->t2 = cos( $this->lat0 );
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$p->x = $x;
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$p->y = $y;
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return $p;
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}
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/* Equirectangular inverse equations--mapping x,y to lat/long
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--------------------------------------------------------- */
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public function inverse( $p ) {
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$p->x -= $this->x0;
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$p->y -= $this->y0;
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$lat = $p->y / $this->a;
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if( abs( $lat ) > Proj4php::$common->HALF_PI ) {
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Proj4php::reportError( "equi:Inv:DataError" );
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}
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$lon = Proj4php::$common->adjust_lon( $this->long0 + $p->x / ($this->a * cos( $this->lat0 )) );
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$p->x = $lon;
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$p->y = $lat;
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}
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}
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Proj4php::$proj['equi'] = new Proj4phpProjEqui();
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