Geography whose interior is the metric ε-buffer of the input on the sphere. The distance argument is always interpreted as meters along the spheroid — there is no useSpheroid flag because Geography is inherently spheroidal.
ST_BestSRID), applies a planar buffer in that zone, and projects the result back to lon/lat. This produces accurate results for inputs that fit inside a single UTM zone (~6° wide). For larger inputs the same accuracy caveats apply as for ST_Buffer on Geometry with useSpheroid = true.
useSpheroid is not accepted for Geography inputs. The 3-argument form
ST_Buffer(geom, distance, useSpheroid: Boolean) from the Geometry overload is
rejected when the first argument is a Geography (Geography is inherently
spheroidal, so the flag would be redundant or contradictory). It raises
IllegalArgumentException. Drop the useSpheroid argument, or — for a planar
buffer — convert to Geometry first via ST_GeogToGeometry and use the Geometry
overload of ST_Buffer.parameters string accepts the same JTS-style key/value pairs used by ST_Buffer for Geometry:
| Key | Default | Allowed values |
|---|---|---|
quad_segs | 8 | positive integer — segments per quadrant in curved corners |
endcap | round | round, flat, butt, square |
join | round | round, mitre (or miter), bevel |
mitre_limit (or miter_limit) | 5.0 | positive decimal |
side | both | both, left, right (single-sided buffer for linestrings) |
- A negative
distanceMetersshrinks polygons (returning a smaller polygon, possiblyEMPTYwhen the radius exceeds the polygon’s narrowest dimension); for points and lines a negative buffer always produces an empty result. - The output
Geographypreserves the input’s SRID. If the input has no SRID set, the result is normalized to WGS84 (EPSG:4326).
Signatures
Parameters
The geography to buffer.
The buffer radius, in meters along the spheroid. Negative values shrink polygons.
Optional JTS-style buffer style parameters (see the table above).
Return type
The buffered geography.

