Package org.apache.sis.referencing.operation.transform

Conversions or transformations of multi-dimensional coordinate points.

See: Description

Interface Summary

Interface	Description
LinearTransform	A usually affine, or otherwise a projective transform, which convert coordinates using only linear equations.
MathTransformProvider	An object capable to create Math­Transform instances from given parameter values.

Class Summary

Class	Description
AbstractMathTransform	Provides a default implementation for most methods required by the Math­Transform interface.
AbstractMathTransform1D	Base class for math transforms that are known to be one-dimensional in all cases.
AbstractMathTransform2D	Base class for math transforms that are known to be two-dimensional in all cases.
ContextualParameters	The parameters that describe a sequence of normalize → non-linear kernel → denormalize transforms as a whole.
DatumShiftTransform	Transforms between two CRS (usually geographic) based on different datum.
DefaultMathTransformFactory	Low level factory for creating math transforms.
DefaultMathTransformFactory.Context	Source and target coordinate systems for which a new parameterized transform is going to be used.
EllipsoidToCentricTransform	Transform from two- or three- dimensional ellipsoidal coordinates to (geo)centric coordinates.
InterpolatedGeocentricTransform	Transforms between two geographic CRS by performing geocentric translations interpolated from a grid file.
InterpolatedMolodenskyTransform	Transforms between two geographic CRS by performing geocentric translations interpolated from a grid file, but using Molodensky approximation.
InterpolatedTransform	Transforms between two CRS by performing translations interpolated from a grid file.
MathTransforms	Utility methods creating or working on Math­Transform instances.
MolodenskyTransform	Two- or three-dimensional datum shift using the (potentially abridged) Molodensky transformation.
PassThroughTransform	Transform which passes through a subset of ordinates to another transform.
TransferFunction	The function converting raster sample values to geophysics values.
TransformSeparator	Extracts a sub-transform from a given Math­Transform and source or target dimension indices.

Enum Summary

Enum	Description
ContextualParameters.MatrixRole	Whether a matrix is used for normalization or denormalization before or after a non-linear operation.
EllipsoidToCentricTransform.TargetType	Whether the output coordinate system is Cartesian or Spherical.
IterationStrategy	Strategy for iterating over the point arrays given to Abstract­Math­Transform.transform(…) methods.

Package org.apache.sis.referencing.operation.transform Description

Conversions or transformations of multi-dimensional coordinate points. Math­Transform provides a single API for coordinate conversions or transformations, including map projections. Each Math­Transform instances can:

• transform a single point,
• transform efficiently an array of coordinates,
• transform a Java2D Shape (Math­Transform2D only),
• compute the transform derivative at a location (for advanced users),
• be concatenated in a conversion or transformation chain.

Math­Transform are truly n-dimensional, but specialized implementations for 1D and 2D cases are provided for performance reasons or for inter-operability with Java2D. In the 2D case, Apache SIS provides instances of the standard Affine­Transform class when possible.

This package does not include map projections, which are a special kind of transforms defined in their own projection package.

Creating math transforms

Math­Transform instances can be created either directly or indirectly. The recommended way is the indirect one: first find the coordinate operation (generally from a pair of source and target CRS), then invoke Coordinate­Operation.get­Math­Transform(). However sophisticated users can also create math transforms explicitely from a group of parameter values using the math transform factory.

Non-spatial coordinates

Math­Transform usually performs conversions or transformations from points given in a source coordinate reference system to coordinate values for the same points in the target coordinate reference system. However the conversions are not necessarily between CRS; a Math­Transform can also be used for converting the sample values in a raster for example. Such kind of transforms are named transfer functions.

Since:

0.5

Defined in the sis-referencing module