GeoJSON

GeoJSON
Bestandsextensie	.json
MIME-type	application/json
Ontwikkeld door	http://geojson.org/
Portaal    Informatica

GeoJSON is an open standard format for encoding collections of simple geographical features along with their non-spatial attributes using JavaScript Object Notation. The features include points (therefore addresses and locations), line strings (therefore streets, highways and boundaries), polygons (countries, provinces, tracts of land), and multi-part collections of these types. GeoJSON features need not represent entities of the physical world only; mobile routing and navigation apps, for example, might describe their service coverage using GeoJSON.

Historie

Het formaat is niet opgesteld door een formele organisatie, maar door een werkgrope van ontwikkelaars, de GeoJSON format working group vanaf maart 2007. De specificatie was klaar in juni 2008.

Voorbeeld

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [102.0, 0.6]
      },
      "properties": {
        "prop0": "value0"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
        ]
      },
      "properties": {
        "prop1": 0.0,
        "prop0": "value0"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0],
            [100.0, 0.0]
          ]
        ]
      },
      "properties": {
        "prop1": {
          "this": "that"
        },
        "prop0": "value0"
      }
    }
  ]
}

Geometries

Geometry primitives

Type	Examples
Point		{ "type": "Point", "coordinates": [30, 10] }
LineString		{ "type": "LineString", "coordinates": [ [30, 10], [10, 30], [40, 40] ] }
Polygon		{ "type": "Polygon", "coordinates": [ [[30, 10], [40, 40], [20, 40], [10, 20], [30, 10]] ] }
		{ "type": "Polygon", "coordinates": [ [[35, 10], [45, 45], [15, 40], [10, 20], [35, 10]], [[20, 30], [35, 35], [30, 20], [20, 30]] ] }

Multipart geometries

Type	Examples
MultiPoint		{ "type": "MultiPoint", "coordinates": [ [10, 40], [40, 30], [20, 20], [30, 10] ] }
MultiLineString		{ "type": "MultiLineString", "coordinates": [ [[10, 10], [20, 20], [10, 40]], [[40, 40], [30, 30], [40, 20], [30, 10]] ] }
MultiPolygon		{ "type": "MultiPolygon", "coordinates": [ [ [[30, 20], [45, 40], [10, 40], [30, 20]] ], [ [[15, 5], [40, 10], [10, 20], [5, 10], [15, 5]] ] ] }
		{ "type": "MultiPolygon", "coordinates": [ [ [[40, 40], [20, 45], [45, 30], [40, 40]] ], [ [[20, 35], [10, 30], [10, 10], [30, 5], [45, 20], [20, 35]], [[30, 20], [20, 15], [20, 25], [30, 20]] ] ] }

Software

Het GeoJSON formaat wordt ondersteund door een groot aantal programma's waaronder OpenLayers, Leaflet, Geoforge software, GeoServer, GeoDjango, GDAL, Safe Software FME, en CartoDB,

Het is ook mogelijk GeoJSON te gebruiken met PostGIS en Mapnik,. Beide behandelen het formaat via de GDAL OGR-conversie bibliotheek. Bing Maps, Yahoo! en Google bieden ondersteuning voor GeoJSON in hun API-diensten. GitHub biedt ook GeoJSON rendering.

Externe links

• http://geojson.org/
• http://geojson.org/geojson-spec.html
• http://www.directionsmag.com/article.php?article_id=2550
• http://blog.programmableweb.com/2008/08/27/3-top-data-formats-for-map-mashups-kml-georss-and-geojson/
• http://www.geowebguru.com/articles/97-technical-overview-geojson
• http://googlegeodevelopers.blogspot.com/2009/05/build-on-top-of-your-public-latitude.html