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ST_BUFFER ​

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

See also:

Syntax ​

sql
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 ​

sql
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))