Geo functions
These functions can be used when working with and analysing geospatial data.
| Function | Description |
|---|---|
geo::area() | Calculates the area of a geometry |
geo::bearing() | Calculates the bearing between two geolocation points |
geo::centroid() | Calculates the centroid of a geometry |
geo::distance() | Calculates the distance between two geolocation points |
geo::hash::decode() | Decodes a geohash into a geometry point |
geo::hash::encode() | Encodes a geometry point into a geohash |
geo::area
The geo::area function calculates the area of a geometry.
API DEFINITIONgeo::area(geometry) -> number
The following example shows this function, and its output, when used in a RETURN statement:
RETURN geo::area({
type: "Polygon",
coordinates: [[
[-0.38314819, 51.37692386], [0.1785278, 51.37692386],
[0.1785278, 51.61460570], [-0.38314819, 51.61460570],
[-0.38314819, 51.37692386]
]]
});
0.13350018278702186
If the argument is not a geometry type, then an EMPTY value will be returned:
RETURN geo::area(12345);
null
geo::bearing
The geo::bearing function calculates the bearing between two geolocation points.
API DEFINITIONgeo::bearing(point, point) -> number
The following example shows this function, and its output, when used in a RETURN statement:
RETURN geo::area({
RETURN geo::bearing( (51.509865, -0.118092), (-0.118092, 51.509865) );
-31.913259585079818
If either argument is not a geolocation point, then an EMPTY value will be returned:
RETURN geo::bearing(12345, true);
null
geo::centroid
The geo::centroid function calculates the centroid between two geolocation points.
API DEFINITIONgeo::centroid(geometry) -> number
The following example shows this function, and its output, when used in a RETURN statement:
RETURN geo::centroid({
type: "Polygon",
coordinates: [[
[-0.38314819, 51.37692386], [0.1785278, 51.37692386],
[0.1785278, 51.61460570], [-0.38314819, 51.61460570],
[-0.38314819, 51.37692386]
]]
});
{
"type": "Point",
"coordinates": [
-0.10231019499999999,
51.49576478
]
}
If either argument is not a geometry type, then an EMPTY value will be returned:
RETURN geo::centroid(12345);
null
geo::distance
The geo::distance function calculates the haversine distance, in metres, between two geolocation points.
API DEFINITIONgeo::distance(point, point) -> number
The following example shows this function, and its output, when used in a RETURN statement:
RETURN geo::distance( (51.509865, -0.118092), (-0.118092, 51.509865) );
7491494.807105545
If either argument is not a geolocation point, then an EMPTY value will be returned:
RETURN geo::distance(12345, true);
null
geo::hash::decode
The geo::hash::decode function converts a geohash into a geolocation point.
API DEFINITIONgeo::hash::decode(point) -> string
The following example shows this function, and its output, when used in a RETURN statement:
RETURN geo::hash::decode("mpuxk4s24f51");
{
"type": "Point",
"coordinates": [
51.50986494496465,
-0.11809204705059528
]
}
If the argument is not a geolocation point, then an EMPTY value will be returned:
RETURN geo::hash::decode(12345);
null
geo::hash::encode
The geo::hash::encode function converts a geolocation point into a geohash.
API DEFINITIONgeo::hash::encode(point) -> string
The function accepts a second argument, which determines the accuracy and granularity of the geohash.
API DEFINITIONgeo::hash::encode(point, number) -> string
The following example shows this function, and its output, when used in a RETURN statement:
RETURN geo::hash::encode( (51.509865, -0.118092) );
"mpuxk4s24f51"
The following example shows this function with two arguments, and its output, when used in a select statement:
RETURN geo::hash::encode( (51.509865, -0.118092), 5 );
"mpuxk"
If the first argument is not a geolocation point, then an EMPTY value will be returned:
RETURN geo::hash::encode(12345);
null