ST_BUFFER ​

Computes a POLYGON or MULTIPOLYGON representing all points within a specified distance from a GEOGRAPHY object.

See also:

• ST_UNION
• ST_INTERSECTION

Syntax ​

ST_BUFFER(<input>, <radius>, <num_seg_quarter_circle> = 8)

Arguments ​

• <input>: The GEOGRAPHY to calculate the buffer around
• <radius>: Distance in meters. Negative values shrink the GEOGRAPHY instead of expanding it
• <num_seg_quarter_circle>: Number of line segments used to approximate a quarter circle (default 8)

Returns ​

Returns a GEOGRAPHY representing the buffer area. Special cases include:

• A negative radius applied to points or lines returns an empty GEOGRAPHY
• A negative radius applied to polygons may result in an empty GEOGRAPHY if the shape is completely removed

Example ​

SELECT ST_AsText(ST_Buffer('POINT(0 0)'::GEOGRAPHY, 10, 2));
-- POLYGON((0.00897 0,0.00635 -0.00639,0 -0.00903,-0.00635 -0.00639,-0.00897 0,-0.00635 0.00639,0 0.00903,0.00635 0.00639,0.00897 0))