• Create source and target coordinate systems, which may or may not be two-dimensional.
• Create the coordinate transformation with {@link org.geotools.ct.CoordinateTransformationFactory}.

The CoordinateTransformationFactory class analyze source and target coordinate systems and try to build a transformation path. It can swap axis order and orientation when necessary (for example from ({@link org.geotools.cs.AxisOrientation#NORTH NORTH},{@link org.geotools.cs.AxisOrientation#WEST WEST}) to ({@link org.geotools.cs.AxisOrientation#EAST EAST},{@link org.geotools.cs.AxisOrientation#NORTH NORTH})), apply units conversions and of course performs map projections.

CoordinateTransformationFactory is a kind of high-level API. User wanting more control on transformation creation can use a low-level API: {@link org.geotools.ct.MathTransformFactory}. For example, a mercator cylindrical projection can be created by the following code:

{@link org.geotools.ct.MathTransformFactory} factory = MathTransformFactory.getDefault();
{@link javax.media.jai.ParameterList} parameters = factory.getMathTransformProvider("Mercator_1SP").getParameterList();
parameters.setParameter("semi_major", 6378137.0);
parameters.setParameter("semi_minor", 6356752.314);
{@link org.geotools.ct.MathTransform} projection = factory.createParameterizedTransform(parameters);
    

The "Mercator_1SP" string is the classification name for the mercator cylindrical projection. This package support the following classification names:

Notes on transformation accuracy

Incompatibles changes since last release

• All occurences of org.geotools.ct.TransformException need to be replaced by org.opengis.referencing.operation.TransformException.
• All occurences of org.geotools.ct.NoninvertibleTransformException need to be replaced by org.opengis.referencing.operation.NoninvertibleTransformException.