ST_ASGEOJSON

Converts shapes of the GEOGRAPHY data type to the GeoJSON format.

The GeoJSON standard specifies that GeoJSON points are WGS 84 coordinates, and GeoJSON line segments are planar edges, meaning straight cartesian lines. However, contrary to that, in Firebolt, the line segments are interpreted as geodesic arcs.

The following image shows an extreme case of the difference between these. Both lines show the LineString from the GeoJSON string {"coordinates": [[-0.12457505963581639,51.5006710219584],[-74.04448100812115,40.68923977267272]],"type": "LineString"} that connect the Statue of Liberty in New York City and Big Ben in London. The gray line represents the LineString as a straight Cartesian line, following the GeoJSON standard. In contrast, the red line interprets the LineString as a geodesic arc, consistent with Firebolt’s approach.

An example showing the interpretation of a GeoJSON string according to the GeoJSON standard and in Firebolt.

Syntax

ST_ASGEOJSON(<object>)

Parameters

Parameter	Description	Supported input types
`<object>`	The `GEOGRAPHY` object to convert to GeoJSON format.	`GEOGRAPHY`

Return Type

ST_ASGEOJSON returns a value of type TEXT.

Example

The following query creates a GEOGRAPHY object from the WKT representation of a Point at specified longitude and latitude coordinates and converts it to GeoJSON format:

SELECT ST_ASGEOJSON(ST_GEOGFROMTEXT('POINT(-73.98551041593687 40.75793403395676)')) AS result

Returns

result (TEXT)
’{“type”:”Point”,”coordinates”:[-73.98551041593687,40.75793403395676]}’