Geokit is a PHP toolkit to solve geo-related tasks like:
- Distance calculations.
- Heading, midpoint and endpoint calculations.
- Rectangular bounding box calculations.
Install the latest version with Composer.
composer require geokit/geokit
Check the Packagist page for all available versions.
A Math instance can be used to perform geographic calculations on Position and BoundingBox instances.
The World Geodetic System 1984 (WGS84) is exclusively used as the coordinate reference system.
$math = new Geokit\Math();
A math instance provides two methods to calculate the distance between 2 points on the Earth's surface:
distanceHaversine(Geokit\Position $from, Geokit\Position $to)
: Calculates the approximate sea level great circle (Earth) distance between two points using the Haversine formula.distanceVincenty(Geokit\Position $from, Geokit\Position $to)
: Calculates the geodetic distance between two points using the Vincenty inverse formula for ellipsoids.
$distance1 = $math->distanceHaversine($from, $to);
$distance2 = $math->distanceVincenty($from, $to);
Both methods return a Distance instance.
The circle()
method calculates a closed circle Polygon given a center, radius
and steps for precision.
$circlePolygon = $math->circle(
new Geokit\Position(8.50207515, 49.50042565),
Geokit\Distance::fromString('5km'),
32
);
Other useful methods are:
heading(Geokit\Position $from, Geokit\Position $to)
: Calculates the (initial) heading from the first point to the second point in degrees.midpoint(Geokit\Position $from, Geokit\Position $to)
: Calculates an intermediate point on the geodesic between the two given points.endpoint(Geokit\Position $start, float $heading, Geokit\Distance $distance)
: Calculates the destination point along a geodesic, given an initial heading and distance, from the given start point.
A Distance instance allows for a convenient representation of a distance unit of measure.
$distance = new Geokit\Distance(1000); // Defaults to meters
// or
$distance = new Geokit\Distance(1, Geokit\Distance::UNIT_KILOMETERS);
$meters = $distance->meters();
$kilometers = $distance->kilometers();
$miles = $distance->miles();
$yards = $distance->yards();
$feet = $distance->feet();
$inches = $distance->inches();
$nauticalMiles = $distance->nautical();
A Distance can also be created from a string with an optional unit.
$distance = Geokit\Distance::fromString('1000'); // Defaults to meters
$distance = Geokit\Distance::fromString('1000m');
$distance = Geokit\Distance::fromString('1km');
$distance = Geokit\Distance::fromString('100 miles');
$distance = Geokit\Distance::fromString('100 yards');
$distance = Geokit\Distance::fromString('1 foot');
$distance = Geokit\Distance::fromString('1 inch');
$distance = Geokit\Distance::fromString('234nm');
A Position
is a fundamental construct representing a geographical position in
x
(or longitude
) and y
(or latitude
) coordinates.
Note, that x
/y
coordinates are kept as is, while longitude
/latitude
are
normalized.
- Longitudes range between -180 and 180 degrees, inclusive. Longitudes above 180 or below -180 are normalized. For example, 480, 840 and 1200 will all be normalized to 120 degrees.
- Latitudes range between -90 and 90 degrees, inclusive. Latitudes above 90 or below -90 are normalized. For example, 100 will be normalized to 80 degrees.
$position = new Geokit\Position(181, 91);
$x = $position->x(); // Returns 181.0
$y = $position->y(); // Returns 91.0
$longitude = $position->longitude(); // Returns -179.0, normalized
$latitude = $position->latitude(); // Returns 89.0, normalized
A BoundingBox instance represents a rectangle in geographical coordinates, including one that crosses the 180 degrees longitudinal meridian.
It is constructed from its left-bottom (south-west) and right-top (north-east) corner points.
$southWest = new Geokit\Position(2, 1);
$northEast = new Geokit\Position(2, 1);
$boundingBox = new Geokit\BoundingBox($southWest, $northEast);
$southWestPosition = $boundingBox->getSouthWest();
$northEastPosition = $boundingBox->getNorthEast();
$center = $boundingBox->getCenter();
$span = $boundingBox->getSpan();
$boolean = $boundingBox->contains($position);
$newBoundingBox = $boundingBox->extend($position);
$newBoundingBox = $boundingBox->union($otherBoundingBox);
With the expand()
and shrink()
methods, you can expand or shrink a
BoundingBox instance by a distance.
$expandedBoundingBox = $boundingBox->expand(
Geokit\Distance::fromString('10km')
);
$shrinkedBoundingBox = $boundingBox->shrink(
Geokit\Distance::fromString('10km')
);
The toPolygon()
method converts the BoundingBox to an equivalent Polygon
instance.
$polygon = $boundingBox->toPolygon();
A Polygon instance represents a two-dimensional shape of connected line segments and may either be closed (the first and last point are the same) or open.
$polygon = new Geokit\Polygon([
new Geokit\Position(0, 0),
new Geokit\Position(1, 0),
new Geokit\Position(1, 1)
]);
$closedPolygon = $polygon->close();
/** @var Geokit\Position $position */
foreach ($polygon as $position) {
}
$polygon->contains(Geokit\Position(0.5, 0.5)); // true
/** @var Geokit\BoundingBox $boundingBox */
$boundingBox = $polygon->toBoundingBox();
Copyright (c) 2011-2019 Jan Sorgalla. Released under the MIT License.
Geokit has been inspired and/or contains ported code from the following libraries: