Name
ST_Scale — Scales a geometry by given factors.
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);
Descripción
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 multiplied by the scale factor.
![[Note]](../images/note.png)
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Anterior a 1.3.4, esta función daba errores si se utilizaba con geometrias que contenían CURVES. Esto se corrigió en 1.3.4+ |
Availability: 1.1.0.
Mejorado: 2.0.0 se introdujo soporte para superficies poliédricas, Triangulos y TIN.
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.
Ejemplos
--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
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LINESTRING(1 1,3 3)