Package org.geotools.referencing.operation.transform

Class LinearTransform1D

Object

Formattable

AbstractMathTransform

LinearTransform1D

All Implemented Interfaces:

Serializable, MathTransform, MathTransform1D, LinearTransform

public class LinearTransform1D
extends AbstractMathTransform
implements MathTransform1D, LinearTransform, Serializable

A one dimensional, linear transform. Input values x are converted into output values y using the following equation:

y = offset + scale×x This class is the same as a 2×2 affine transform. However, this specialized LinearTransform1D class is faster. It is defined there because extensively used by GridCoverage2D.

Since:

2.0

Author:

Martin Desruisseaux (IRD)

See Also:

LogarithmicTransform1D, ExponentialTransform1D, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class AbstractMathTransform

AbstractMathTransform.Inverse

Field Summary

Fields

Modifier and Type	Field	Description
static LinearTransform1D	IDENTITY	The identity transform.
double	offset	The value to add to input values.
double	scale	The value which is multiplied to input values.

Fields inherited from class Formattable

SINGLE_LINE

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	LinearTransform1D(double scale, double offset)	Constructs a new linear transform.

Method Summary

Modifier and Type	Method	Description
static LinearTransform1D	create(double scale, double offset)	Constructs a new linear transform.
double	derivative(double value)	Gets the derivative of this function at a value.
Matrix	derivative(Position 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 this transform as an affine transform 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, which is 1.
int	getTargetDimensions()	Gets the dimension of output points, which is 1.
int	hashCode()	Returns a hash value for this transform.
MathTransform1D	inverse()	Creates the inverse transform of this object.
boolean	isIdentity()	Tests whether this transform does not move any points.
boolean	isIdentity(double tolerance)	Tests whether this transform does not move any points by using the provided tolerance.
double	transform(double value)	Transforms the specified value.
void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts)	Transforms a list of coordinate point ordinal values.
void	transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts)	Transforms a list of coordinate point ordinal values.

Methods inherited from class AbstractMathTransform

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

Field Detail

IDENTITY

public static final LinearTransform1D IDENTITY

The identity transform.

scale

public final double scale

The value which is multiplied to input values.

offset

public final double offset

The value to add to input values.

Constructor Detail

LinearTransform1D

protected LinearTransform1D(double scale,
                            double offset)

Constructs a new linear transform. This constructor is provided for subclasses only. Instances should be created using the factory method, which may returns optimized implementations for some particular argument values.

Parameters:

scale - The scale term in the linear equation.

offset - The offset term in the linear equation.

Method Detail

create

public static LinearTransform1D create(double scale,
                                       double offset)

Constructs a new linear transform.

Parameters:

scale - The scale term in the linear equation.

offset - The offset term in the linear equation.

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. The number of parameters depends on the matrix size. Only matrix elements different from their default value will be included in this group.

Overrides:

getParameterValues in class AbstractMathTransform

Returns:

A copy of the parameter values for this math transform.

See Also:

Operation.getParameterValues()

getSourceDimensions

public int getSourceDimensions()

Gets the dimension of input points, which is 1.

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, which is 1.

Specified by:

getTargetDimensions in interface MathTransform

Specified by:

getTargetDimensions in class AbstractMathTransform

Returns:

The dimension of output points.

getMatrix

public Matrix getMatrix()

Returns this transform as an affine transform matrix.

Specified by:

getMatrix in interface LinearTransform

Returns:

A copy of the underlying matrix.

inverse

public MathTransform1D inverse()
                        throws NoninvertibleTransformException

Creates the inverse transform of this object.

Specified by:

inverse in interface MathTransform

Specified by:

inverse in interface MathTransform1D

Overrides:

inverse in class AbstractMathTransform

Returns:

The inverse transform.

Throws:

NoninvertibleTransformException - if the transform can't be inversed.

isIdentity

public boolean isIdentity()

Tests whether this transform does not move any points.

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 by using the provided tolerance. This method work in the same way than XMatrix.isIdentity(double).

Specified by:

isIdentity in interface LinearTransform

Parameters:

tolerance - The tolerance factor.

Returns:

true if this transform is the identity one

Since:

2.3.1

derivative

public Matrix derivative(Position point)
                  throws TransformException

Gets the derivative of this transform at a point. This implementation is different from the default AbstractMathTransform.derivative(java.awt.geom.Point2D) implementation in that no coordinate point is required and Double.NaN may be a legal output value for some users.

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).

Throws:

TransformException - if the derivative can't be evaluated at the specified point.

derivative

public double derivative(double value)

Gets the derivative of this function at a value.

Specified by:

derivative in interface MathTransform1D

Parameters:

value - The value where to evaluate the derivative.

Returns:

The derivative at the specified point.

transform

public double transform(double value)

Transforms the specified value.

Specified by:

transform in interface MathTransform1D

Parameters:

value - The value to transform.

Returns:

the transformed value.

transform

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

Transforms a list of coordinate point ordinal values.

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 a list of coordinate point ordinal values.

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.

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.