org.apache.sis.referencing.operation.builder

Class LinearTransformBuilder

Object

LinearTransformBuilder

public class LinearTransformBuilder
extends Object

Creates a linear (usually affine) transform which will map approximatively the given source points to the given target points. The transform coefficients are determined using a least squares estimation method, with the assumption that source points are precise and all uncertainty is in the target points.

Implementation note: The quantity that current implementation tries to minimize is not strictly the squared Euclidian distance. The current implementation rather processes each target dimension independently, which may not give the same result than if we tried to minimize the squared Euclidian distances by taking all dimensions in account together. This algorithm may change in future SIS versions.

Since:

0.5

See Also:

LinearTransform, Line, Plane

Defined in the sis-referencing module

Constructor Summary

Constructors

Constructor and Description
LinearTransformBuilder() Creates a new linear transform builder.

Method Summary

Methods

Modifier and Type	Method and Description
double[]	correlation() Returns the correlation coefficients of the last transform created by create(), or null if none.
LinearTransform	create() Creates a linear transform approximation from the source points to the target points.
void	setSourcePoints(DirectPosition... points) Sets the source points.
void	setTargetPoints(DirectPosition... points) Sets the target points.
String	toString() Returns a string representation of this builder for debugging purpose.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LinearTransformBuilder

public LinearTransformBuilder()

Creates a new linear transform builder.

Method Detail

setSourcePoints

public void setSourcePoints(DirectPosition... points)
                     throws MismatchedDimensionException

Sets the source points. The number of points shall be the same than the number of target points.

Limitation: in current implementation, the source points must be one or two-dimensional. This restriction may be removed in a future SIS version.

Parameters:

points - The source points, assumed precise.

Throws:

MismatchedDimensionException - if at least one point does not have the expected number of dimensions.

setTargetPoints

public void setTargetPoints(DirectPosition... points)
                     throws MismatchedDimensionException

Sets the target points. The number of points shall be the same than the number of source points. Target points can have any number of dimensions (not necessarily 2), but all points shall have the same number of dimensions.

Parameters:

points - The target points, assumed uncertain.

Throws:

MismatchedDimensionException - if not all points have the same number of dimensions.

create

public LinearTransform create()

Creates a linear transform approximation from the source points to the target points. This method assumes that source points are precise and all uncertainty is in the target points.

Returns:

The fitted linear transform.

correlation

public double[] correlation()

Returns the correlation coefficients of the last transform created by create(), or null if none. If non-null, the array length is equals to the number of target dimensions.

Returns:

Estimation of correlation coefficients for each target dimension, or null.

toString

@Debug
public String toString()

Returns a string representation of this builder for debugging purpose.

Overrides:

toString in class Object

Returns:

A string representation of this builder.