Polygon

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Next version — This documentation describes a major version that is not yet the current stable release of spatial-types.

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What is a Polygon?

A Polygon represents an area bounded by one exterior ring and, optionally, interior rings that form holes. A valid polygon has closed LineString boundaries.

Spatial Types stores the supplied boundaries without checking closure or hole topology. Construction alone does not establish polygon validity. Use explicit geometric validation when your application requires it.

Polygon — Supported representations

Availability in the current version of Spatial Types:

Coordinate layout	Geometry Mutable	Geometry Immutable	Geography Mutable	Geography Immutable
XY	✅	✅	✅	✅
XYZ	✅	✅	✅	✅
XYM	✅	✅	✅	✅
XYZM	✅	✅	✅	✅

Creating the illustrated objects

The examples recreate the labelled objects above using Geometry in XY. Composer’s autoloader must already be loaded. Variable names match the point letters in the illustration.

Immutable objects

<?php

use LongitudeOne\SpatialTypes\Types\Dimension2\Geometry\PointImmutable;
use LongitudeOne\SpatialTypes\Types\Dimension2\Geometry\LineStringImmutable;
use LongitudeOne\SpatialTypes\Types\Dimension2\Geometry\PolygonImmutable;

// Immutable objects must be fully initialized through their constructors.

$a = new PointImmutable(6.5, 7);
$b = new PointImmutable(28.5, 7);
$c = new PointImmutable(25, 20);
$d = new PointImmutable(10.5, 18.5);
$e = new PointImmutable(43, 20);
$f = new PointImmutable(68.5, 20);
$g = new PointImmutable(68.5, 6);
$h = new PointImmutable(43, 6);
$i = new PointImmutable(50, 15.5);
$j = new PointImmutable(61.5, 15.5);
$k = new PointImmutable(61.5, 10);
$l = new PointImmutable(50, 10);

$firstRing = new LineStringImmutable([$a, $b, $c, $d, $a]);
$firstPolygon = new PolygonImmutable([$firstRing]);
$exteriorRing = new LineStringImmutable([$e, $f, $g, $h, $e]);
$interiorRing = new LineStringImmutable([$i, $j, $k, $l, $i]);
$polygonWithHole = new PolygonImmutable([$exteriorRing, $interiorRing]);

Mutable objects

<?php

use LongitudeOne\SpatialTypes\Types\Dimension2\Point;
use LongitudeOne\SpatialTypes\Types\Dimension2\LineString;
use LongitudeOne\SpatialTypes\Types\Dimension2\Polygon;

$a = new Point(6.5, 7);
$b = new Point(28.5, 7);
$c = new Point(25, 20);
$d = new Point(10.5, 18.5);
$e = new Point(43, 20);
$f = new Point(68.5, 20);
$g = new Point(68.5, 6);
$h = new Point(43, 6);
$i = new Point(50, 15.5);
$j = new Point(61.5, 15.5);
$k = new Point(61.5, 10);
$l = new Point(50, 10);

$firstRing = new LineString([$a, $b, $c, $d, $a]);
$firstPolygon = new Polygon([$firstRing]); // Using the constructor.
$exteriorRing = new LineString([$e, $f, $g, $h, $e]);
$interiorRing = new LineString([$i, $j, $k, $l, $i]);
// Starting with the exterior ring and adding the hole with a method.
$polygonWithHole = new Polygon([$exteriorRing])->addRing($interiorRing);