ST_ScaleGeom

Introduction: This function scales the input geometry (geometry) to a new size. It does this by multiplying the coordinates of the input geometry with corresponding values from another geometry (factor) representing the scaling factors.

To scale the geometry relative to a point other than the true origin (e.g., scaling a polygon in place using its centroid), you can use the three-geometry variant of this function. This variant requires an additional geometry (origin) representing the "false origin" for the scaling operation. If no origin is provided, the scaling occurs relative to the true origin, with all coordinates of the input geometry simply multiplied by the corresponding scale factors.

Note

This function is designed for scaling 2D geometries. While it currently doesn't support scaling the Z and M coordinates, it preserves these values during the scaling operation.

Format:

ST_ScaleGeom(geometry: Geometry, factor: Geometry, origin: Geometry)

ST_ScaleGeom(geometry: Geometry, factor: Geometry)

Since: v1.7.0

SQL Example:

SELECT ST_Scale(
        ST_GeomFromWKT('POLYGON ((0 0, 0 1.5, 1.5 1.5, 1.5 0, 0 0))'),
       ST_Point(3, 2)
)

Output:

POLYGON ((0 0, 0 3, 4.5 3, 4.5 0, 0 0))

SQL Example:

SELECT ST_Scale(
        ST_GeomFromWKT('POLYGON ((0 0, 0 1.5, 1.5 1.5, 1.5 0, 0 0))'),
       ST_Point(3, 2), ST_Point(1, 2)
)

Output:

POLYGON ((-2 -2, -2 1, 2.5 1, 2.5 -2, -2 -2))