GeoJSON Basics¶
GeoJSON is an open standardized format for geodata based on the Javascript Object Notation (JSON) used to encode geographic data structures. This section is based on RFC 7946.
GeoJSON is a textual representation of geographical data and its non-spatial attributes. A GeoJSON document contains one object with can be a Feature, a FeatureCollection or a Geometry. The object has to have a property type which is one of the following:
Point¶
The coordinates array of the Point object usually contains two to three dimensions representing longitude, latitude and possibly elevation in this order.
Example Point¶
{
"type": "Point",
"coordinates": [8.53362,50.16192]
}
MultiPoint¶
Each entry in the coordinates array is a Point coordinates array.
Example MultiPoint¶
{
"type": "MultiPoint",
"coordinates": [
[13.35,52.5145], [13.377,52.5162]
]
}
LineString¶
A LineString coordinates array consists of two or more Point coordinates arrays.
Example LineString¶
{
"type": "LineString",
"coordinates": [
[13.35,52.5145], [13.377,52.5162]
]
}
MultiLineString¶
As the name suggests, a MultiLineString coordinates array contains LineString coordinates arrays.
Example MultiLineString¶
{
"type": "MultiLineString",
"coordinates": [
[
[78.0422,27.1744],[78.0422,27.1733]
],
[
[78.0422,27.1730],[78.0422,27.1719]
]
]
}
View this MultiLineString on a map
Polygon¶
Each element of a Polygon coordinates array has to be a special LineString coordinates array. This special kind is called a 'linear ring' in the RFC specification. In a 'linear ring' the first and last elements in the coordinates array are the same.
If the Polygon contains more than one 'linear ring', that is a shape with holes, the first ring must describe the exterior ring, following the holes. The coordinates of the exterior ring must be listed counterclockwise, the coordinates of the hole(s) clockwise.
Example Polygon¶
{
"type": "Polygon",
"coordinates": [
[
[-77.0578,38.87254],[-77.0584,38.87],[-77.0555,38.8688],[-77.0531,38.8706],[-77.0546,38.8729],[-77.0578,38.87254]
],
[
[-77.0567,38.8715],[-77.0555,38.8717],[-77.0549,38.8708],[-77.0558,38.8702],[-77.0569,38.8706],[-77.0567,38.8715]
]
]
}
Multipolygon¶
In a Multipolygon, each of the elements of the coordinates array is defined as a Polygon above.
Example Multipolygon¶
{
"type": "MultiPolygon",
"coordinates": [
[
[[31.1330,29.9780],[31.1354,29.9780],[31.1354,29.9801],[31.1330,29.9801],[31.1330,29.9780]],
[[31.1296,29.9750],[31.1319,29.9750],[31.1319,29.9769],[31.1296,29.9769],[31.1296,29.9750]],
[[31.1277,29.9720],[31.1287,29.9720],[31.1287,29.9729],[31.1277,29.9729],[31.1277,29.9720]]
]
]
}
View this MultiPolygon on a map
Feature¶
A Feature object contains two members besides the type property: geometry and properties
The geometry can be any of the aforementioned types or a GeoJSON null value.
The value of properties can be any GeoJSON object or a GeoJSON null value.
Example Feature¶
{
"type": "Feature",
"geometry": {
"type": "LineString",
"coordinates": [
[13.35,52.5145], [13.377,52.5162]
]
},
"properties": {
"prop0": "value0",
"prop1": "value1"
}
}
FeatureCollection¶
A FeatureCollection contains an array of Features, contained in a member called features.
Example FeatureCollection¶
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-2.960847,
53.430828
]
},
"properties": {
"@ns:com:here:xyz": {
"tags": [
"football",
"stadium"
]
},
"name": "Anfield",
"amenity": "Football Stadium",
"capacity": 54074,
"popupContent": "Home of Liverpool Football Club"
}
}
]
}
View this FeatureCollection on a map
GeometryCollection¶
A GeometryCollection is a collection of zero or more geometry objects like the ones above in an array member called geometries
Warning¶
GeometryCollection is not supported by xyzmaps space Hub. It is included here for completeness.
Example GeometryCollection¶
{
"type": "GeometryCollection",
"geometries": [
{
"type": "Point",
"coordinates": [8.53362,50.16192]
},
{
"type": "LineString",
"coordinates": [
[13.35,52.5145], [13.377,52.5162]
]
}
]
}