| New file |
|---|
| 0,0 → 1,121 |
|---|
| <?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 MOLLWEIDE |
| |
| PURPOSE: Transforms input longitude and latitude to Easting and |
| Northing for the MOllweide projection. The |
| longitude and latitude must be in radians. The Easting |
| and Northing values will be returned in meters. |
| |
| PROGRAMMER DATE |
| ---------- ---- |
| D. Steinwand, EROS May, 1991; Updated Sept, 1992; Updated Feb, 1993 |
| S. Nelson, EDC Jun, 2993; Made corrections in precision and |
| number of iterations. |
| |
| ALGORITHM REFERENCES |
| |
| 1. 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. |
| |
| 2. 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. |
| ****************************************************************************** */ |
| |
| class Proj4phpProjMoll { |
| /* Initialize the Mollweide projection |
| ------------------------------------ */ |
| |
| public function init() { |
| //no-op |
| } |
| |
| /* Mollweide forward equations--mapping lat,long to x,y |
| ---------------------------------------------------- */ |
| public function forward( $p ) { |
| |
| /* Forward equations |
| ----------------- */ |
| $lon = $p->x; |
| $lat = $p->y; |
| |
| $delta_lon = Proj4php::$common->adjust_lon( $lon - $this->long0 ); |
| $theta = $lat; |
| $con = Proj4php::$common->PI * sin( $lat ); |
| |
| /* Iterate using the Newton-Raphson method to find theta |
| ----------------------------------------------------- */ |
| for( $i = 0; true; ++$i ) { |
| $delta_theta = -($theta + sin( $theta ) - $con) / (1.0 + cos( $theta )); |
| $theta += $delta_theta; |
| if( abs( $delta_theta ) < Proj4php::$common->EPSLN ) |
| break; |
| if( $i >= 50 ) { |
| Proj4php::reportError( "moll:Fwd:IterationError" ); |
| //return(241); |
| } |
| } |
| $theta /= 2.0; |
| |
| /* If the latitude is 90 deg, force the x coordinate to be "0 . false easting" |
| this is done here because of precision problems with "cos(theta)" |
| -------------------------------------------------------------------------- */ |
| if( Proj4php::$common->PI / 2 - abs( $lat ) < Proj4php::$common->EPSLN ) |
| $delta_lon = 0; |
| $x = 0.900316316158 * $this->a * $delta_lon * cos( $theta ) + $this->x0; |
| $y = 1.4142135623731 * $this->a * sin( $theta ) + $this->y0; |
| |
| $p->x = $x; |
| $p->y = $y; |
| return $p; |
| } |
| |
| /** |
| * |
| * @param type $p |
| * @return type |
| */ |
| public function inverse( $p ) { |
| #$theta; |
| #$arg; |
| |
| /* Inverse equations |
| ----------------- */ |
| $p->x-= $this->x0; |
| //~ $p->y -= $this->y0; |
| $arg = $p->y / (1.4142135623731 * $this->a); |
| |
| /* Because of division by zero problems, 'arg' can not be 1.0. Therefore |
| a number very close to one is used instead. |
| ------------------------------------------------------------------- */ |
| if( abs( $arg ) > 0.999999999999 ) |
| $arg = 0.999999999999; |
| $theta = asin( $arg ); |
| $lon = Proj4php::$common->adjust_lon( $this->long0 + ($p->x / (0.900316316158 * $this->a * cos( $theta ))) ); |
| if( $lon < (-Proj4php::$common->PI) ) |
| $lon = -Proj4php::$common->PI; |
| if( $lon > Proj4php::$common->PI ) |
| $lon = Proj4php::$common->PI; |
| $arg = (2.0 * $theta + sin( 2.0 * $theta )) / Proj4php::$common->PI; |
| if( abs( $arg ) > 1.0 ) |
| $arg = 1.0; |
| $lat = asin( $arg ); |
| //return(OK); |
| |
| $p->x = $lon; |
| $p->y = $lat; |
| |
| return $p; |
| } |
| } |
| |
| Proj4php::$proj['moll'] = new Proj4phpProjMoll(); |