PostGIS

ST_TransScale
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ST_TransScale

7.16. Affine Transformations

Name

ST_TransScale — Translates and scales a geometry by given offsets and factors.

Synopsis

geometry +`*`+ST_TransScale*(`geometry `geomA, float deltaX, float deltaY, float XFactor, float YFactor`)`;

Description

Translates the geometry using the deltaX and deltaY args, then scales it using the XFactor, YFactor args, working in 2D only.

ST_TransScale(geomA, deltaX, deltaY, XFactor, YFactor) is short-hand for ST_Affine(geomA, XFactor, 0, 0, 0, YFactor, 0, 0, 0, 1, deltaX*XFactor, deltaY*YFactor, 0).

Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

Availability: 1.1.0.

check This function supports 3d and will not drop the z-index.

check This method supports Circular Strings and Curves.

Examples

SELECT ST_AsEWKT(ST_TransScale(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), 0.5, 1, 1, 2));
          st_asewkt
-----------------------------
 LINESTRING(1.5 6 3,1.5 4 1)


--Buffer a point to get an approximation of a circle, convert to curve and then translate 1,2 and scale it 3,4
  SELECT ST_AsText(ST_Transscale(ST_LineToCurve(ST_Buffer('POINT(234 567)', 3)),1,2,3,4));
                                                          st_astext
------------------------------------------------------------------------------------------------------------------------------
 CURVEPOLYGON(CIRCULARSTRING(714 2276,711.363961030679 2267.51471862576,705 2264,698.636038969321 2284.48528137424,714 2276))

PostGIS

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