Returns the geometry transformed using the given transform definition.
ST_SpatialRefSys::ST_TransformGeom(geom,target-transform-definition[, source-transform-definition])
Name | Type | Description |
---|---|---|
geom |
ST_Geometry |
The geometry to be transformed |
target-transform-definition |
LONG VARCHAR |
The target spatial reference system transform definition text |
source-transform-definition |
LONG VARCHAR |
The source spatial reference system transform definition text. If not specified, the transform definition from the spatial reference system of the geom parameter is used. |
ST_Geometry Returns the input geometry transformed using the given transform definition.
The spatial reference system identifier of the result is sa_planar_unbounded (with SRID 2147483646).
The ST_TransformGeom method transforms a single geometry given the transform definition of the destination. The transformation is performed using the PROJ.4 library. This method can be used in select situations when the appropriate spatial reference systems have not yet been created in the database. If the appropriate spatial reference systems are available, the ST_Transform method is often more appropriate.
Transformations from a lat/long system to a Cartesian system can be problematic for polar points. If the database server is unable to transform a point close to the North or South pole, the latitude value of the point is shifted a small distance (slightly more than 1e-10 radians) away from the pole, and along the same longitude, so that the transformation can succeed.
SQL/MM (ISO/IEC 13249-3: 2006) Vendor extension
The following example returns the result Point (-5387692.968586 4763459.253243)
.
SELECT ST_SpatialRefSys::ST_TransformGeom( NEW ST_Point(-63.57,44.65,4326), '+proj=robin +lon_0=0 +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m no_defs' ).ST_AsText('DecimalDigits=6') |
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