PostGIS
Synopsis
geometry +`*`+ST_Scale*(`geometry `geomA, float XFactor,
float YFactor, float ZFactor`)`;
geometry +`*`+ST_Scale*(`geometry `geomA, float XFactor,
float YFactor`)`;
geometry +`*`+ST_Scale*(`geometry `geom, geometry
factor`)`;
geometry +`*`+ST_Scale*(`geometry `geom, geometry factor,
geometry origin`)`;
Description
Scales the geometry to a new size by multiplying the ordinates with the corresponding factor parameters.
The version taking a geometry as the factor parameter allows passing
a 2d, 3dm, 3dz or 4d point to set scaling factor for all supported
dimensions. Missing dimensions in the factor point are equivalent to
no scaling the corresponding dimension.
The three-geometry variant allows a "false origin" for the scaling to be passed in. This allows "scaling in place", for example using the centroid of the geometry as the false origin. Without a false origin, scaling takes place relative to the actual origin, so all coordinates are just multipled by the scale factor.
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Availability: 1.1.0.
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Enhanced: 2.2.0 support for scaling all dimension (factor parameter)
was introduced.
Enhanced: 2.5.0 support for scaling relative to a local origin
(origin parameter) was introduced.
This
function supports Polyhedral surfaces.
This
function supports 3d and will not drop the z-index.
This
method supports Circular Strings and Curves.
This
function supports Triangles and Triangulated Irregular Network Surfaces
(TIN).
This
function supports M coordinates.
Examples
--Version 1: scale X, Y, Z
SELECT ST_AsEWKT(ST_Scale(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), 0.5, 0.75, 0.8));
st_asewkt
--------------------------------------
LINESTRING(0.5 1.5 2.4,0.5 0.75 0.8)
--Version 2: Scale X Y
SELECT ST_AsEWKT(ST_Scale(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), 0.5, 0.75));
st_asewkt
----------------------------------
LINESTRING(0.5 1.5 3,0.5 0.75 1)
--Version 3: Scale X Y Z M
SELECT ST_AsEWKT(ST_Scale(ST_GeomFromEWKT('LINESTRING(1 2 3 4, 1 1 1 1)'),
ST_MakePoint(0.5, 0.75, 2, -1)));
st_asewkt
----------------------------------------
LINESTRING(0.5 1.5 6 -4,0.5 0.75 2 -1)
--Version 4: Scale X Y using false origin
SELECT ST_AsText(ST_Scale('LINESTRING(1 1, 2 2)', 'POINT(2 2)', 'POINT(1 1)'::geometry));
st_astext
---------------------
LINESTRING(1 1,3 3)