README

phpgeo provides abstractions to geographical coordinates (including support for different ellipsoids) and allows you to calculate geographical distances between coordinates with high precision.

phpgeo - A Simple Geo Library for PHP

Requirements

Minimum required PHP version is 7.3. phpgeo fully supports PHP 8 and is tested up to PHP 8.2.

The 3.x releases require PHP >= 7.2 but don't get feature updates any longer. Bugfixes will be backported.

The 2.x releases require PHP >= 7.0 but don't get feature updates any longer. Bugfixes won't be backported.

The 1.x release line has support for PHP >= 5.4. Bugfixes won't be backported.

Documentation

The documentation is available at https://phpgeo.marcusjaschen.de/

Installation

Using Composer, just add it to your composer.json by running:

composer require mjaschen/phpgeo

Upgrading

Update the version constraint in the project's composer.json and run composer update or require the new version by running:

composer require mjaschen/phpgeo:^4.0

License

Starting with version 2.0.0 phpgeo is licensed under the MIT license. Older versions were GPL-licensed.

Features

Info: Please visit the documentation site for complete and up-to-date documentation with many examples!

phpgeo provides the following features (follow the links for examples):

abstractions of several geometry objects (coordinate/point, line, polyline/GPS track, polygon
support for different ellipsoids, e.g. WGS-84
length/distance/perimeter calculations with different implementations (Haversine, Vincenty)
Geofence calculation, i.e. answering the question "Is this point contained in that area/polygon?" and other intersection checks between different geometries
formatting and output of geometry objects (GeoJSON, nice strings, e. g. 18° 54′ 41″ -155° 40′ 42″)
calculation of bearing angle between two points (spherical or with Vincenty's formula)
calculation of a destination point for a given starting point, bearing angle, and distance (spherical or with Vincenty's formula)
calculation of the perpendicular distance between a point and a line
calculation of the Cardinal Distances between two points
getting segments of a polyline /polygon,
reversing direction of polyline/polygon

Examples/Usage

This list is incomplete, please visit the documentation site for the full monty of documentation and examples!

Distance between two coordinates (Vincenty's Formula)

Use the calculator object directly:

<?php

use Location\Coordinate;
use Location\Distance\Vincenty;

$coordinate1 = new Coordinate(19.820664, -155.468066); // Mauna Kea Summit
$coordinate2 = new Coordinate(20.709722, -156.253333); // Haleakala Summit

$calculator = new Vincenty();

echo $calculator->getDistance($coordinate1, $coordinate2); // returns 128130.850 (meters; ≈128 kilometers)

or call the getDistance() method of a Coordinate object by injecting a calculator object:

<?php

use Location\Coordinate;
use Location\Distance\Vincenty;

$coordinate1 = new Coordinate(19.820664, -155.468066); // Mauna Kea Summit
$coordinate2 = new Coordinate(20.709722, -156.253333); // Haleakala Summit

echo $coordinate1->getDistance($coordinate2, new Vincenty()); // returns 128130.850 (meters; ≈128 kilometers)

Simplifying a polyline

Polylines can be simplified to save storage space or bandwidth. Simplification is done with the Ramer–Douglas–Peucker algorithm (AKA Douglas-Peucker algorithm).

<?php

use Location\Coordinate;
use Location\Polyline;
use Location\Distance\Vincenty;

$polyline = new Polyline();
$polyline->addPoint(new Coordinate(10.0, 10.0));
$polyline->addPoint(new Coordinate(20.0, 20.0));
$polyline->addPoint(new Coordinate(30.0, 10.0));

$processor = new Simplify($polyline);

// remove all points which perpendicular distance is less
// than 1500 km from the surrounding points.
$simplified = $processor->simplify(1500000);

// simplified is the polyline without the second point (which
// perpendicular distance is ~1046 km and therefore below
// the simplification threshold)

Polygon contains a point (e.g. "GPS geofence")

phpgeo has a polygon implementation which can be used to determinate if a point is contained in it or not. A polygon consists of at least three points. Points are instances of the Coordinate class.

Warning: The calculation gives wrong results if the polygons has points on both sides of the 180/-180 degrees meridian.

<?php

use Location\Coordinate;
use Location\Polygon;

$geofence = new Polygon();

$geofence->addPoint(new Coordinate(-12.085870,-77.016261));
$geofence->addPoint(new Coordinate(-12.086373,-77.033813));
$geofence->addPoint(new Coordinate(-12.102823,-77.030938));
$geofence->addPoint(new Coordinate(-12.098669,-77.006476));

$outsidePoint = new Coordinate(-12.075452, -76.985079);
$insidePoint = new Coordinate(-12.092542, -77.021540);

var_dump($geofence->contains($outsidePoint)); // returns bool(false) the point is outside the polygon
var_dump($geofence->contains($insidePoint)); // returns bool(true) the point is inside the polygon

Formatted output of coordinates

You can format a coordinate in different styles.

Decimal Degrees

<?php

use Location\Coordinate;
use Location\Formatter\Coordinate\DecimalDegrees;

$coordinate = new Coordinate(19.820664, -155.468066); // Mauna Kea Summit

echo $coordinate->format(new DecimalDegrees());

Degrees/Minutes/Seconds (DMS)

<?php

use Location\Coordinate;
use Location\Formatter\Coordinate\DMS;

$coordinate = new Coordinate(18.911306, -155.678268); // South Point, HI, USA

$formatter = new DMS();

echo $coordinate->format($formatter); // 18° 54′ 41″ -155° 40′ 42″

$formatter->setSeparator(", ")
    ->useCardinalLetters(true)
    ->setUnits(DMS::UNITS_ASCII);

echo $coordinate->format($formatter); // 18° 54' 41" N, 155° 40' 42" W

GeoJSON

<?php

use Location\Coordinate;
use Location\Formatter\Coordinate\GeoJSON;

$coordinate = new Coordinate(18.911306, -155.678268); // South Point, HI, USA

echo $coordinate->format(new GeoJSON()); // { "type" : "point" , "coordinates" : [ -155.678268, 18.911306 ] }

Development

Run Tests

Before submitting a pull request, please be sure to run all checks and tests and ensure everything is green.

lint PHP files for syntax errors: composer ci:lint
run static analysis with Psalm and report errors: composer ci:psalm
run unit tests with PHPUnit: composer ci:tests

To run all checks and tests at once, just use composer ci.

Of course, it's possible to use the test runners directly, e.g. for PHPUnit:

./vendor/bin/phpunit

Psalm:

./vendor/bin/psalm

Running GitHub Actions locally

It's possible to run the whole CI test matrix locally with act:

act --rm -P ubuntu-latest=shivammathur/node:latest

Credits

Marcus Jaschen mail@marcusjaschen.de and all contributors
Chris Veness - JavaScript implementation of the Vincenty formula for distance calculation
Ersts,P.J., Horning, N., and M. Polin[Internet] Perpendicular Distance Calculator(version 1.2.2) Documentation. American Museum of Natural History, Center for Biodiversity and Conservation. Available from http://biodiversityinformatics.amnh.org/open_source/pdc. Accessed on 2013-07-07.
W. Randolph Franklin, PNPOLY - Point Inclusion in Polygon Test Documentation

omelya / phpgeo

Maintainers

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