geokit / geokit
Geo-Toolkit for PHP
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Requires
- php: >=5.3.3
README
Geokit is a PHP toolkit to solve geo-related tasks like:
- Distance calculations.
- Heading, midpoint and endpoint calculations.
- Rectangular bounding box calculations.
Installation
Install the latest version with Composer.
composer require geokit/geokit
Check the Packagist page for all available versions.
Reference
Distance
A Distance instance allows for a convenient representation of a distance unit of measure.
use Geokit\Distance; $distance = new Distance(1000); // Defaults to meters // or $distance = new Distance(1, 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.
use Geokit\Distance; $distance = Distance::fromString('1000'); // Defaults to meters $distance = Distance::fromString('1000m'); $distance = Distance::fromString('1km'); $distance = Distance::fromString('100 miles'); $distance = Distance::fromString('100 yards'); $distance = Distance::fromString('1 foot'); $distance = Distance::fromString('1 inch'); $distance = Distance::fromString('234nm');
Position
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.
use Geokit\Position; $position = new 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
BoundingBox
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.
use Geokit\BoundingBox; use Geokit\Position; $southWest = Position::fromXY(2, 1); $northEast = Position::fromXY(2, 1); $boundingBox = BoundingBox::fromCornerPositions($southWest, $northEast); $southWestPosition = $boundingBox->southWest(); $northEastPosition = $boundingBox->northEast(); $center = $boundingBox->center(); $span = $boundingBox->span(); $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.
use Geokit\Distance; $expandedBoundingBox = $boundingBox->expand( Distance::fromString('10km') ); $shrinkedBoundingBox = $boundingBox->shrink( Distance::fromString('10km') );
The toPolygon()
method converts the BoundingBox to an equivalent Polygon
instance.
$polygon = $boundingBox->toPolygon();
Polygon
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.
use Geokit\BoundingBox; use Geokit\Polygon; use Geokit\Position; $polygon = Polygon::fromPositions( Position::fromXY(0, 0), Position::fromXY(1, 0), Position::fromXY(1, 1) ); $closedPolygon = $polygon->close(); /** @var Position $position */ foreach ($polygon as $position) { } $polygon->contains(Position::fromXY(0.5, 0.5)); // true /** @var BoundingBox $boundingBox */ $boundingBox = $polygon->toBoundingBox();
Functions
Geokit provides several functions to perform geographic calculations.
Distance calculations
distanceHaversine(Position $from, Position $to)
: Calculates the approximate sea level great circle (Earth) distance between two points using the Haversine formula.distanceVincenty(Position $from, Position $to)
: Calculates the geodetic distance between two points using the Vincenty inverse formula for ellipsoids.
use function Geokit\distanceHaversine; use function Geokit\distanceVincenty; $distance1 = distanceHaversine($from, $to); $distance2 = distanceVincenty($from, $to);
Both functions return a Distance instance.
Transformations
The circle()
function calculates a closed circle Polygon given a center,
radius and steps for precision.
use Geokit\Distance; use Geokit\Position; use function Geokit\circle; $circlePolygon = circle( Position::fromXY(8.50207515, 49.50042565), Distance::fromString('5km'), 32 );
Other calculations
Other useful functions are:
heading(Position $from, Position $to)
: Calculates the (initial) heading from the first point to the second point in degrees.midpoint(Position $from, Position $to)
: Calculates an intermediate point on the geodesic between the two given points.endpoint(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.
License
Copyright (c) 2011-2022 Jan Sorgalla. Released under the MIT License.