Module operations 

Geometry construction and transformation operations.

ST_Buffer, ST_Envelope, ST_Union — produce new geometries from existing ones.

Functions

st_buffer

ST_Buffer(geom, distance_meters) → Polygon.

st_envelope

ST_Envelope(geom) → Polygon — bounding box as a polygon.

st_union

ST_Union(a, b) → Geometry — merge two geometries.