aeris/spatial

Representations of spatial data

v1.3.1 2015-08-31 20:43 UTC

BSD

• Edan Schwartz

README

Representations of spatial data.

Installation

composer require aeris/spatial

Components

GeometryConverter

The GeometryConverter component may be used to convert geometry data between different formats. The following conversions are currently supported:

• GeoJson Polygon to WKT
• GeoJson MultiPolygon to WKT

Additional conversions can be made by using Geometry objects directly, via the ConvertibleGeometryInterface::FromArray() and ConvertibleGeometryInterface::toWkt() methods (see Geometry component documentation)

Examples

use Aeris\Spatial\GeometryConverter;

$geoJson = json_encode([
  'type' => 'Polygon',
  'coordinates' => [
    [
      [100, 0],
      [101, 0],
      [101, 1],
      [100, 1],
      [100, 0],
    ]
  ]
]);
$wkt = GeometryConverter::geoJsonToWkt($geoJson);

$this->assertEquals(
  'POLYGON((100 0,101 0,101 1,100 1,100 0))',
  $wkt
);

Geometry

Geometry components are object representations of spatial data structures. Objects implementing \Aeris\Spatial\Geometry\ConvertibleGeometryInterface may be easily converted between array and WKT (string) formats using the FromArray(array $data) and toWkt() methods

Some Geometry components may implement additional conversion methods. For example, \Aeris\Spatial\Geometry\MultiPolygon implements a FromFeatureCollection() method, which makes it easy to convert a GeoJson feature collection to a MultiPolygon object.

Examples

The following example demonstrates converting a GeoJson FeatureCollection into a MultiPolygon object.

$geoJson = [
  'type' => 'FeatureCollection',
  'features' => [
    [
      'type' => 'Feature',
      'geometry' => [
        'type' => 'Polygon',
        'coordinates' => [
          [
            [100, 0],
            [100, 100],
            [0, 100],
            [0, 0],
            [100, 0],
          ]
        ]
      ],
    ],
    [
      'type' => 'Feature',
      'geometry' => [
        'type' => 'Polygon',
        'coordinates' => [
          [
            [200, 0],
            [200, 200],
            [0, 200],
            [0, 0],
            [200, 0]
          ]
        ]
      ]
    ]
  ],
];

$mPoly = MultiPolygon::FromFeatureCollection($geoJson);

$this->assertEquals([
  Polygon::FromArray([
    [
      [100, 0],
      [100, 100],
      [0, 100],
      [0, 0],
      [100, 0]
    ]
  ]),
  Polygon::FromArray([
    [
      [200, 0],
      [200, 200],
      [0, 200],
      [0, 0],
      [200, 0]
    ]
  ])
], $mPoly->getPolygons());

You could then use the MultiPolygon object to execute a MySql spatial query:

$myQuery = 'SELECT * FROM `places` ' .
 'WHERE ST_CONTAINS(GeomFromText(' . $mPoly->toWKT() . '), `places`.`point`)' 

Util

The Aeris\Spatial\Util namespace contains some utility function for working with spatial components.

Util\bearing

Returns the direction (in degrees) between two coordinates.

$minneapolis = new Coordinate(-93.251953125, 44.9336963896947);
$chicago = new Coordinate(-87.71484375, 41.80407814427237);

Util\bearing($minneapolis, $chicago); // 125.93766052151
Util\bearing($chicago, $minneapolis); // 309.74293632484

Util\compassDirection

Returns the compass rose direction between two coordinates.

$minneapolis = new Coordinate(-93.251953125, 44.9336963896947);
$edenPrarie = new Coordinate(-93.4768295288086, 44.85148787683413);

Util\compassDirection($minneapolis, $edenPrarie); // 'SW'
Util\compassDirection($edenPrarie, $minneapolis); // 'NE'

Possible return values:

• NNE
• NE
• ENE
• E
• ESE
• SE
• SSE
• S
• SSW
• SW
• WSW
• W
• WNW
• NW
• NNW
• N