org.geotools.referencing.operation.transform

Class IdentityTransform

Object

Formattable

AbstractMathTransform

IdentityTransform

All Implemented Interfaces:

Serializable, LinearTransform, MathTransform

public class IdentityTransform
extends AbstractMathTransform
implements LinearTransform, Serializable

The identity transform. The data are only copied without any transformation. This class is used for identity transform of dimension greater than 2. For 1D and 2D identity transforms, LinearTransform1D and AffineTransform already provide their own optimisations.

Since:

2.0

Author:

Martin Desruisseaux (IRD)

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class AbstractMathTransform

AbstractMathTransform.Inverse

Field Summary

Fields inherited from class Formattable

SINGLE_LINE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IdentityTransform(int dimension) Constructs an identity transform of the specified dimension.

Method Summary

Modifier and Type	Method and Description
static LinearTransform	create(int dimension) Constructs an identity transform of the specified dimension.
Matrix	derivative(DirectPosition point) Gets the derivative of this transform at a point.
boolean	equals(Object object) Compares the specified object with this math transform for equality.
Matrix	getMatrix() Returns a copy of the identity matrix.
ParameterDescriptorGroup	getParameterDescriptors() Returns the parameter descriptors for this math transform.
ParameterValueGroup	getParameterValues() Returns the matrix elements as a group of parameters values.
int	getSourceDimensions() Gets the dimension of input points.
int	getTargetDimensions() Gets the dimension of output points.
int	hashCode() Returns a hash value for this transform.
MathTransform	inverse() Returns the inverse transform of this object, which is this transform itself
boolean	isIdentity() Tests whether this transform does not move any points.
boolean	isIdentity(double tolerance) Tests whether this transform does not move any points.
DirectPosition	transform(DirectPosition ptSrc, DirectPosition ptDst) Copies the values from ptSrc to ptDst.
void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Transforms an array of floating point coordinates by this transform.
void	transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Transforms an array of floating point coordinates by this transform.

Methods inherited from class AbstractMathTransform

createTransformedShape, derivative, ensureNonNull, formatWKT, getName, needCopy, normalizeAngle, rollLongitude, transform, transform, transform

Methods inherited from class Formattable

cleanupThreadLocals, toString, toWKT, toWKT, toWKT, toWKT

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface MathTransform

toWKT, transform, transform

Constructor Detail

IdentityTransform

protected IdentityTransform(int dimension)

Constructs an identity transform of the specified dimension.

Method Detail

create

public static LinearTransform create(int dimension)

Constructs an identity transform of the specified dimension.

isIdentity

public boolean isIdentity()

Tests whether this transform does not move any points. This implementation always returns true.

Specified by:

isIdentity in interface MathTransform

Overrides:

isIdentity in class AbstractMathTransform

Returns:

true if this MathTransform is an identity transform; false otherwise.

isIdentity

public boolean isIdentity(double tolerance)

Tests whether this transform does not move any points. This implementation always returns true.

Specified by:

isIdentity in interface LinearTransform

Parameters:

tolerance - The tolerance factor.

Returns:

true if this transform is the identity one

getSourceDimensions

public int getSourceDimensions()

Gets the dimension of input points.

Specified by:

getSourceDimensions in interface MathTransform

Specified by:

getSourceDimensions in class AbstractMathTransform

Returns:

The dimension of input points.

getTargetDimensions

public int getTargetDimensions()

Gets the dimension of output points.

Specified by:

getTargetDimensions in interface MathTransform

Specified by:

getTargetDimensions in class AbstractMathTransform

Returns:

The dimension of output points.

getParameterDescriptors

public ParameterDescriptorGroup getParameterDescriptors()

Returns the parameter descriptors for this math transform.

Overrides:

getParameterDescriptors in class AbstractMathTransform

Returns:

The parameter descriptors for this math transform, or null.

See Also:

OperationMethod.getParameters()

getParameterValues

public ParameterValueGroup getParameterValues()

Returns the matrix elements as a group of parameters values.

Overrides:

getParameterValues in class AbstractMathTransform

Returns:

A copy of the parameter values for this math transform.

See Also:

Operation.getParameterValues()

getMatrix

public Matrix getMatrix()

Returns a copy of the identity matrix.

Specified by:

getMatrix in interface LinearTransform

Returns:

A copy of the underlying matrix.

derivative

public Matrix derivative(DirectPosition point)

Gets the derivative of this transform at a point. For an identity transform, the derivative is the same everywhere.

Specified by:

derivative in interface MathTransform

Overrides:

derivative in class AbstractMathTransform

Parameters:

point - The coordinate point where to evaluate the derivative.

Returns:

The derivative at the specified point (never null).

transform

public DirectPosition transform(DirectPosition ptSrc,
                                DirectPosition ptDst)

Copies the values from ptSrc to ptDst. Overrides the super-class method for performance reason.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

ptSrc - the specified coordinate point to be transformed.

ptDst - the specified coordinate point that stores the result of transforming ptSrc, or null.

Returns:

the coordinate point after transforming ptSrc and storing the result in ptDst, or a newly created point if ptDst was null.

Since:

2.2

transform

public void transform(float[] srcPts,
                      int srcOff,
                      float[] dstPts,
                      int dstOff,
                      int numPts)

Transforms an array of floating point coordinates by this transform.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

srcPts - the array containing the source point coordinates.

srcOff - the offset to the first point to be transformed in the source array.

dstPts - the array into which the transformed point coordinates are returned. May be the same than srcPts.

dstOff - the offset to the location of the first transformed point that is stored in the destination array.

numPts - the number of point objects to be transformed.

transform

public void transform(double[] srcPts,
                      int srcOff,
                      double[] dstPts,
                      int dstOff,
                      int numPts)

Transforms an array of floating point coordinates by this transform.

Specified by:

transform in interface MathTransform

Parameters:

srcPts - the array containing the source point coordinates.

srcOff - the offset to the first point to be transformed in the source array.

dstPts - the array into which the transformed point coordinates are returned. May be the same than srcPts.

dstOff - the offset to the location of the first transformed point that is stored in the destination array.

numPts - the number of point objects to be transformed.

inverse

public MathTransform inverse()

Returns the inverse transform of this object, which is this transform itself

Specified by:

inverse in interface MathTransform

Overrides:

inverse in class AbstractMathTransform

Returns:

The inverse transform.

hashCode

public int hashCode()

Returns a hash value for this transform. This value need not remain consistent between different implementations of the same class.

Overrides:

hashCode in class AbstractMathTransform

equals

public boolean equals(Object object)

Compares the specified object with this math transform for equality.

Overrides:

equals in class AbstractMathTransform

Parameters:

object - The object to compare with this transform.

Returns:

true if the given object is a transform of the same class and if, given identical source position, the transformed position would be the equals.