Skip to main content

ST_Buffer

Creates a buffer polygon at a specified distance around a geometry.

Syntax​

ST_Buffer(geometry, distance)

Parameters​

ParameterTypeDescription
geometryGeometryInput geometry
distanceFloat64Buffer distance in geometry units

Returns​

TypeDescription
Binary (WKB)Buffer polygon as WKB with geoarrow.wkb metadata

Examples​

Buffer Around Point​

SELECT ST_Buffer(ST_Point(0, 0), 10.0);
-- Returns a circle polygon with radius 10

Buffer Around LineString​

SELECT ST_Buffer(ST_GeomFromText('LINESTRING(0 0, 10 0)'), 5.0);
-- Returns a rounded rectangle

Buffer with Column Distance​

SELECT id, ST_Buffer(geom, buffer_radius) as buffer_zone
FROM features;

Negative Buffer (Polygon Shrinking)​

SELECT ST_Buffer(
    ST_GeomFromText('POLYGON((0 0, 10 0, 10 10, 0 10, 0 0))'),
    -2.0
);
-- Returns a smaller polygon inset by 2 units

Notes​

  • Positive distance creates an outward buffer
  • Negative distance creates an inward buffer (for polygons only)
  • Buffer distance is in the same units as the geometry coordinates
  • For geographic coordinates, distance is in degrees
  • Uses GEOS library for computation with default segment count

See Also​