org.geotools.referencing.operation.builder

Class BursaWolfTransformBuilder

Object

MathTransformBuilder

BursaWolfTransformBuilder

public class BursaWolfTransformBuilder
extends MathTransformBuilder

Builds MathTransform setup as BursaWolf transformation from a list of MappedPosition. The calculation uses least square method. Calculated parameters can be used for following operations:

The equations:

 X = q * R * x  +  T ,             

Where X is the Matrix of destination points, q is the scale, R is the rotation Matrix, x is the Matrix of source points and T is matrix of translation. Expressing the errors, we get this:

        Err =  A * Dx + l 

where Err is the Error Matrix, A is Matrix of derivations, Dx is Matrix of difference changes of 7 parameters, and l is value of DX, DY, DZ for calculated from approximate values. Using the least square method to minimalize the errors we get this result:

  Dx = (ATA)-1 ATl  

Since:

2.4

Author:

Jan Jezek

Field Summary

Fields inherited from class MathTransformBuilder

mtFactory

Constructor Summary

Constructors

Constructor and Description
BursaWolfTransformBuilder(List<MappedPosition> vectors) Creates a BursaWolfTransformBuilder.

Method Summary

Modifier and Type	Method and Description
protected MathTransform	computeMathTransform() Returns MathtTransform setup as BursaWolf transformation.
protected GeneralMatrix	getA() Glues the submatrix of derivations into the A matrix.
BursaWolfParameters	getBursaWolfParameters(GeodeticDatum Datum) Returns Bursa Wolf Transformation parameters.
Class<? extends CartesianCS>	getCoordinateSystemType() Returns the required coordinate system type, which is cartesian CS.
int	getDimension() Returns the dimension for source and target CRS, which is 2.
protected GeneralMatrix	getDq() Generates partial derivative in q (scale factor).
protected GeneralMatrix	getDRalfa() Generates partial derivative with respect to alfa.
protected GeneralMatrix	getDRbeta() Generates partial derivative with respect to beta.
protected GeneralMatrix	getDRgamma() Generates partial derivative with respect to gamma.
GeneralMatrix	getDxMatrix() Method that claculates the parameters by iteration.
protected GeneralMatrix	getl() Calculates the matrix of errors from aproximate values of prameters.
int	getMinimumPointCount() Returns the minimum number of points required by this builder, which is 3.
protected double[]	getParameters() Returns array of doubles of transformation parameters (dx, dy, dz, ex, ey, ez, scale).
protected GeneralMatrix	getRalfa() Generates rotation matrix around X axis.
protected GeneralMatrix	getRbeta() Generates rotation matrix around Y axis.
protected GeneralMatrix	getRgamma() Generates rotation matrix around Z axis.
protected GeneralMatrix	getx() Fills the x matrix by coordinates of source points.
protected GeneralMatrix	getX() Fills the x matrix by coordinates of destination points.
void	setTargetGeodeticDatum(GeodeticDatum gd)
protected GeneralMatrix	specialMul(GeneralMatrix R, GeneralMatrix x) Method for multiplying matrix (3,3) by matrix of coordintes (3 number of coordinates,1)

Methods inherited from class MathTransformBuilder

getErrorStatistics, getMappedPositions, getMathTransform, getName, getSourceCRS, getSourcePoints, getTargetCRS, getTargetPoints, getTransformation, printPoints, setMappedPositions, setSourcePoints, setTargetPoints, toString

Methods inherited from class Object

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

Constructor Detail

BursaWolfTransformBuilder

public BursaWolfTransformBuilder(List<MappedPosition> vectors)

Creates a BursaWolfTransformBuilder.

Parameters:

vectors - list of mapped positions.

Method Detail

getMinimumPointCount

public int getMinimumPointCount()

Returns the minimum number of points required by this builder, which is 3.

Specified by:

getMinimumPointCount in class MathTransformBuilder

Returns:

the minimum number of points required by this builder which is 3.

getDimension

public int getDimension()

Returns the dimension for source and target CRS, which is 2.

Overrides:

getDimension in class MathTransformBuilder

Returns:

dimension for source and target CRS, which is 2.

getCoordinateSystemType

public Class<? extends CartesianCS> getCoordinateSystemType()

Returns the required coordinate system type, which is cartesian CS.

Overrides:

getCoordinateSystemType in class MathTransformBuilder

Returns:

coordinate system type

getx

protected GeneralMatrix getx()

Fills the x matrix by coordinates of source points.

Returns:

x matrix.

getX

protected GeneralMatrix getX()

Fills the x matrix by coordinates of destination points.

Returns:

the X matrix

getRalfa

protected GeneralMatrix getRalfa()

Generates rotation matrix around X axis.

Returns:

rotation Matrix

getRbeta

protected GeneralMatrix getRbeta()

Generates rotation matrix around Y axis.

Returns:

rotation Matrix.

getRgamma

protected GeneralMatrix getRgamma()

Generates rotation matrix around Z axis.

Returns:

rotation Matrix.

getDRalfa

protected GeneralMatrix getDRalfa()

Generates partial derivative with respect to alfa.

Returns:

Matrix, that represents partial derivation of rotation Matrix with respect to alfa.

getDRbeta

protected GeneralMatrix getDRbeta()

Generates partial derivative with respect to beta.

Returns:

Matrix, that represents partial derivation of rotation Matrix with respect to beta.

getDRgamma

protected GeneralMatrix getDRgamma()

Generates partial derivative with respect to gamma.

Returns:

Matrix, that represents partial derivation of rotation Matrix with respect to gamma.

getDq

protected GeneralMatrix getDq()

Generates partial derivative in q (scale factor).

Returns:

rotation Matrix.

getl

protected GeneralMatrix getl()

Calculates the matrix of errors from aproximate values of prameters.

Returns:

the l matrix.

specialMul

protected GeneralMatrix specialMul(GeneralMatrix R,
                                   GeneralMatrix x)

Method for multiplying matrix (3,3) by matrix of coordintes (3 number of coordinates,1)

Parameters:

R - ratrix

x - matrix

Returns:

matrix

getA

protected GeneralMatrix getA()

Glues the submatrix of derivations into the A matrix.

Returns:

A mtarix

getParameters

protected double[] getParameters()

Returns array of doubles of transformation parameters (dx, dy, dz, ex, ey, ez, scale).

Returns:

array of doubles of transformation parameters (dx, dy, dz, ex, ey, ez, scale).

getDxMatrix

public GeneralMatrix getDxMatrix()

Method that claculates the parameters by iteration. The tolarance is set to 1 10_-8 and max �number of steps is set to 20.

Returns:

Matrix of parameters (dx, dy, dz, ex, ey, ez, scale).

getBursaWolfParameters

public BursaWolfParameters getBursaWolfParameters(GeodeticDatum Datum)

Returns Bursa Wolf Transformation parameters.

Parameters:

Datum - The target datum for this parameters.

Returns:

parameters the BursaWolfParameters

setTargetGeodeticDatum

public void setTargetGeodeticDatum(GeodeticDatum gd)

computeMathTransform

protected MathTransform computeMathTransform()
                                      throws FactoryException

Returns MathtTransform setup as BursaWolf transformation.

Specified by:

computeMathTransform in class MathTransformBuilder

Returns:

calculated MathTransform

Throws:

FactoryException - when the size of source and destination point is not the same or if the number of points is too small to define such transformation.