ES|QL ST_BUFFER function
geometry- Expression of type
geo_point,geo_shape,cartesian_pointorcartesian_shape. Ifnull, the function returnsnull. distance-
Buffer distance in the units of the input spatial reference system
Computes a buffer area around the input geometry at the specified distance. The distance is in the units of the input spatial reference system. Positive distances expand the geometry, negative distances shrink it. A distance of zero will return the input geometry unchanged. Points and lines become polygons when buffered, unless a zero distance is provided.
| geometry | distance | result |
|---|---|---|
| cartesian_point | double | cartesian_shape |
| cartesian_point | float | cartesian_shape |
| cartesian_point | integer | cartesian_shape |
| cartesian_point | long | cartesian_shape |
| cartesian_shape | double | cartesian_shape |
| cartesian_shape | float | cartesian_shape |
| cartesian_shape | integer | cartesian_shape |
| cartesian_shape | long | cartesian_shape |
| geo_point | double | geo_shape |
| geo_point | float | geo_shape |
| geo_point | integer | geo_shape |
| geo_point | long | geo_shape |
| geo_shape | double | geo_shape |
| geo_shape | float | geo_shape |
| geo_shape | integer | geo_shape |
| geo_shape | long | geo_shape |
ROW wkt = "POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0))"
| EVAL buffered = ST_BUFFER(TO_GEOSHAPE(wkt), -1)
| wkt:keyword | buffered:geo_shape |
|---|---|
| POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0)) | POLYGON ((1.0 1.0, 1.0 3.0, 3.0 3.0, 3.0 1.0, 1.0 1.0)) |
Negative distance shrinks a polygon
Buffering a 10x10 square by -2 produces a smaller square inset by 2 units on each side.
Buffering a point produces a circle
A point with positive distance becomes a polygon approximating a circle (8 segments per quadrant by default).
Default round end caps on a line
A line buffered with the default round end caps becomes a stadium shape.
