GeoJSON-php

Use GeoJSON data as a PHP Class Object, including handy object methods.

GeoJSON is a great format for sharing mapping data across different systems and programming languages, especially JavaScript. But on its own, GeoJSON is just a block of data. This GeoJSON Object adds handy reference and utility functions to the data, without changing how you would access the data were it an ordinary JavaScript Object.

A Couple Quick Examples

Example GeoJSON Feature

$featureRaw = [
  "type" => "Feature",
  "geometry" => [
    "type" => "Polygon",
    "coordinates" => [[[10,0],[50,10],[40,50],[0,40]]]
  ]
];

$featureObject = new \GeoJSON\Feature( $featureRaw );

echo json_encode( $featureObject ), PHP_EOL;
// {"type":"Feature","geometry":{"type":"Polygon","coordinates":[[[10,0],[50,10],[40,50],[0,40],[10,0]]]}}
// Note that the polygon coordinate ring was automatically "closed" so the first and last points are the same.

echo json_encode( $featureObject->bbox ), PHP_EOL;
// [0,0,50,50]

Example GeoJSON FeatureCollection

$fcRaw = [
  "type" => "FeatureCollection",
  "features" => [
    [
      "type" => "Feature",
      "geometry" => [
        "type" => "Point",
        "coordinates" => [50,10]
      ],
      "properties" => [
        "id" => 1,
        "label" => "First Base"
      ]
    ],
    [
      "type" => "Feature",
      "geometry" => [
        "type" => "Point",
        "coordinates" => [40,50]
      ],
      "properties" => [
        "id" => 2,
        "label" => "Second Base"
      ]
    ],
  ]
];

$myBases = new \GeoJSON\FeatureCollection( $fcRaw );

echo json_encode( $fcObj->bbox ), PHP_EOL;
// [40,10,50,50]

Installation

1. Download or clone this repo.
2. Copy the src/GeoJSON folder into the directory you keep your PHP classes.
3. include the GeoJSON class files, or use the autoloader of your choice.

Reference

There are currently four object classes at your disposal in this script, each starts with the standard GeoJSON data format, then adds a few convenience methods.

• FeatureCollection
• Feature
• Geometry
• Bbox

Methods Common to All GeoJSON-php Classes

Construction:

All class object constructors in GeoJSON-php expect input in the the standard GeoJSON format. See RFC7946 for details.

$fc = new \GeoJSON\FeatureCollection( $featureCollectionData );
$f = new \GeoJSON\Feature( $featureData );
$g = new \GeoJSON\Geometry( $featureGeometryData );

Getting the Bounding-Box

For all classes, the bbox property is automatically calculated when accessed.

$bbox = $g->bbox;                      // Object property access,
$southernmostLatitude = $f['bbox'][0]; // or array access.

Converting to JSON string:

Class methods and housekeeping properties are automatically stripped out by the jsonSerialize() method and when using json_encode( $myGeoJsonObj ).

$jsonString = json_encode( $myFeatureClassObject );

Converting back to an associative array:

You can turn any GeoJSON Class Object back into a simple associative array with the toArray() method.

$plainObject = $myGeoJsonClassObject->toArray();