A PHP-Class for geographic coordinates transformation using proj4 definitions, thanks to a translation from Proj4JS

2.0.16 2024-04-03 04:27 UTC


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PHP-class for proj4 This is a PHP-Class for geographic coordinates transformation using proj4 definitions, thanks to a translation from Proj4JS.

Updated Requirements and Features

To keep up with the relentless pace of PHP versions and best practice, the following features are being implemented on this package:

  • Namespacing.
  • PHP5.4+ syntax (not aiming to be bleeding edge here, just yet)
  • PSR-2 styling
  • PSR-4 autoloader
  • semver release numbers to
  • Full compatibility with composer
  • Tests to come once the above is implemented.

Legacy branches proj4php5.2 and proj4php7.1 will be maintained for older applications that need it.


You can install the package via composer:

composer require proj4php/proj4php


// Use a PSR-4 autoloader for the `proj4php` root namespace.

use proj4php\Proj4php;
use proj4php\Proj;
use proj4php\Point;

// Initialise Proj4
$proj4 = new Proj4php();

// Create two different projections.
$projL93    = new Proj('EPSG:2154', $proj4);
$projWGS84  = new Proj('EPSG:4326', $proj4);

// Create a point.
$pointSrc = new Point(652709.401, 6859290.946, $projL93);
echo "Source: " . $pointSrc->toShortString() . " in L93 <br>";

// Transform the point between datums.
$pointDest = $proj4->transform($projWGS84, $pointSrc);
echo "Conversion: " . $pointDest->toShortString() . " in WGS84<br><br>";

// Source: 652709.401 6859290.946 in L93
// Conversion: 2.3557811127971 48.831938054369 in WGS84

There are also ways to define inline projections. Check and seek for your projection and proj4 or OGC WKT definitions.

Add a new projection from proj4 definition with a name :

// add it to proj4
$proj4->addDef("EPSG:27700",'+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs');

// then Create your projections
$projOSGB36 = new Proj('EPSG:27700',$proj4);

Or without a name :

// Create your projection
$projOSGB36 = new Proj('+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs',$proj4);

You can also create your projection from OGC WKT definition :

$projOSGB36 = new Proj('PROJCS["OSGB 1936 / British National Grid",GEOGCS["OSGB 1936",DATUM["OSGB_1936",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],AUTHORITY["EPSG","6277"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4277"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",49],PARAMETER["central_meridian",-2],PARAMETER["scale_factor",0.9996012717],PARAMETER["false_easting",400000],PARAMETER["false_northing",-100000],AUTHORITY["EPSG","27700"],AXIS["Easting",EAST],AXIS["Northing",NORTH]]',$proj4);

Developing - How to contribute

Feel free to fork us and submit your changes!

OSGeo community project


Proj4php is also an OSGeo community project. See here for further details.