public class ST_Buffer
extends GenericUDF
Generates a new ST_Geometry object that is the buffered version of the input geometry.
Format:
ST_Buffer(geometry ST_Geometry, bufferWidth NUMBER, arcTol NUMBER) - returns a new ST_Geometry which is the buffered version of the specified 2D geometry
If the geometry is geodetic then the geometry is interpreted as long/lat values in WGS84 and the bufferwidth and tolerance are interpreted as meters.
The tolerance is optional.
The tolerance is used in geodetic arc densification and ignored for non-geodetic geometries.
By default the tolerance is 0.05 for geodetic geometries.
Example:
select ST_Buffer(
ST_Point('{ "type": "Point", "coordinates": [0, 5]}', 0), 3
) from hivetable LIMIT 1; -- return {"type":"Polygon", "coordinates":[[[-3,5],[0,2],[3,5]]],"crs":{"type":"name","properties":{"name":"EPSG:0"}}}