GeoPHP is a open-source native PHP library for doing geometry operations. It is written entirely in PHP and can therefore run on shared hosts. It can read and write a wide variety of formats (WKT, WKB, GeoJSON, KML, GPX, GeoRSS). It works with all Simple-Feature geometries (Point, LineString, Polygon, GeometryCollection etc.) and can be used to get centroids, bounding-boxes, area, and a wide variety of other useful information.

geoPHP also helpfully wraps the GEOS php extension so that applications can get a transparent performance increase when GEOS is installed on the server. When GEOS is installed, geoPHP also becomes fully compliant with the OpenGIS® Implementation Standard for Geographic information. This means that you get the full-set of openGIS functions in PHP like Union, IsWithin, Touches etc.

Applications get a useful "core-set" of geometry operations that work in all environments, and an "extended-set" of operations for environments that have GEOS installed. As time and resources allow we will be porting as much as possible to native PHP to enable more operations on hosts without GEOS.

See the 'getting started' section below for references and examples of everything that geoPHP can do.

This project is currently looking for co-maintainers. If you think you can help out, please send me a message. Forks are also welcome, please issue pull requests and I will merge them into the main branch.

Getting Started

• The lastest stable version can always be downloaded at: https://github.com/downloads/phayes/geoPHP/geoPHP.tar.gz
• Read the API Reference at: https://github.com/phayes/geoPHP/wiki/API-Reference
• Examples
  • Using geoPHP as a GIS format converter: http://github.com/phayes/geoPHP/wiki/Example-format-converter
• Other Interesting Links:
  • Learn about GEOS integration at: https://github.com/phayes/geoPHP/wiki/GEOS

Example usage

include_once('geoPHP.inc');

// Polygon WKT example
$polygon = geoPHP::load('POLYGON((1 1,5 1,5 5,1 5,1 1),(2 2,2 3,3 3,3 2,2 2))','wkt');
$area = $polygon->getArea();
$centroid = $polygon->getCentroid();
$centX = $centroid->getX();
$centY = $centroid->getY();

print "This polygon has an area of ".$area." and a centroid with X=".$centX." and Y=".$centY;

// MultiPoint json example
print "<br/>";
$json = 
'{
   "type": "MultiPoint",
   "coordinates": [
       [100.0, 0.0], [101.0, 1.0]
   ]
}';

$multipoint = geoPHP::load($json, 'json');
$multipoint_points = $multipoint->getComponents();
$first_wkt = $multipoint_points[0]->out('wkt');

print "This multipolygon has ".$multipoint->numGeometries()." points. The first point has a wkt representation of ".$first_wkt;

More Examples

The Well Known Text (WKT) and Well Known Binary (WKB) support is ideal for integrating with MySQL's spatial capability. Once you have SELECTed your data with 'AsText('geo_field')' or 'AsBinary('geo_field')', you can put it straight into geoPHP (can be wkt or wkb, but must be the same as how you extracted it from your database):

$geom = geoPHP::load($dbRow,'wkt');

You can collect multiple geometries into one (note that you must use wkt for this):

$geom = geoPHP::load("GEOMETRYCOLLECTION(".$dbString1.",".$dbString2.")",'wkt');

Google's geocoding offering http://code.google.com/apis/maps/documentation/geocoding/ is one of the few out there, and is simply integrated:

$gg = new GoogleGeocode();
$geom = $gg->read('London');

Note that the request is fired off to google as soon as you make call `read()`. You can then output the geometry in any of the formats.

There are four possible parameters for GoogleGeocode->read(), they are:

read(string $address, string $return_type = 'point', bool $bounds = FALSE, bool $return_multiple = FALSE);

Return type may be 'point' or 'bounds'.

Calling get components returns the sub-geometries within a geometry as an array.

$geom2 = $wkt_reader->read("GEOMETRYCOLLECTION(LINESTRING(1 1,5 1,5 5,1 5,1 1),LINESTRING(2 2,2 3,3 3,3 2,2 2))");
$geomComponents = $geom2->getComponents();    //an array of the two linestring geometries
$linestring1 = $geomComponents[0]->getComponents();	//an array of the first linestring's point geometries
$linestring2 = $geomComponents[1]->getComponents();
echo $linestring1[0]->x() . ", " . $linestring1[0]->y();    //outputs '1, 1'

An alternative is to use the getCoordinates() method. Using the above geometry collection of two linestrings,

$geometryArray = $geom2->getCoordinates();
echo $geometryArray[0][0][0] . ", " . $geometryArray[0][0][1];    //outputs '1, 1'

Clearly, more complex analysis is possible.

echo $geom2->envelope()->area();

Credit

Maintainer: Patrick Hayes

Code From:

• sfMapFish Plugin by camptocamp http://www.camptocamp.com
• CIS by GeoMemes Research http://www.geomemes.com
• gisconverter.php by Arnaud Renevier https://github.com/arenevier/gisconverter.php
• Dave Tarc https://github.com/dtarc

Where code from other projects or authors is included, those authors are included in the copyright notice in that file