Example: { loc : { type : "LineString" , coordinates : [ [ -0.09, 51.49 ], [ 2.35, 48.86 ] ] } } GeoJSON is a format for encoding a variety of geographic data structures. Used by various other HTML APIs as well: OpenLayers, Leaflet and through GDAL also PostGIS. Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon and GeometryCollection.