org.geotoolkit.referencing.datum
Class BursaWolfParameters

Object
  FormattableObject
      BursaWolfParameters

All Implemented Interfaces:

Serializable, Cloneable, Formattable

public class BursaWolfParameters
extends FormattableObject
implements Cloneable, Serializable

Parameters for a geographic transformation between two datum. The Bursa Wolf parameters should be applied to geocentric coordinates, where the X axis points towards the Greenwich Prime Meridian, the Y axis points East, and the Z axis points North. The "Bursa-Wolf" formula is expressed in matrix form with 7 parameters:

Since:

1.2

Version:

3.00

Author:

Martin Desruisseaux (IRD)

See Also:

Serialized Form

Module:

referencing/geotk-referencing (download)

View source code for this class

Field Summary

double	dx Bursa Wolf shift in meters.
double	dy Bursa Wolf shift in meters.
double	dz Bursa Wolf shift in meters.
double	ex Bursa Wolf rotation in arc seconds.
double	ey Bursa Wolf rotation in arc seconds.
double	ez Bursa Wolf rotation in arc seconds.
double	ppm Bursa Wolf scaling in parts per million.
GeodeticDatum	targetDatum The target datum for this parameters.

Fields inherited from class FormattableObject

EPSG, GEOTIFF, INTERNAL, OGC, SINGLE_LINE

Constructor Summary

BursaWolfParameters(GeodeticDatum target)
Constructs a transformation info with all parameters set to 0.

Method Summary

BursaWolfParameters	clone() Returns a copy of this object.
boolean	equals(Object object) Compares the specified object with this object for equality.
String	formatWKT(Formatter formatter) Formats the inner part of a Well Known Text (WKT) element.
XMatrix	getAffineTransform() Returns an affine transform that can be used to define this Bursa Wolf transformation.
int	hashCode() Returns a hash value for this object.
boolean	isIdentity() Returns true if this Bursa Wolf parameters performs no operation.
boolean	isTranslation() Returns true if this Bursa Wolf parameters contains only translation terms.
void	setAffineTransform(Matrix matrix, double eps) Sets transformation info from the specified matrix, which must be affine.

Methods inherited from class FormattableObject

getDefaultIndentation, print, setDefaultIndentation, toString, toWKT, toWKT, toWKT

Methods inherited from class Object

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

Field Detail

dx

public double dx

Bursa Wolf shift in meters.

dy

public double dy

Bursa Wolf shift in meters.

dz

public double dz

Bursa Wolf shift in meters.

ex

public double ex

Bursa Wolf rotation in arc seconds.

ey

public double ey

Bursa Wolf rotation in arc seconds.

ez

public double ez

Bursa Wolf rotation in arc seconds.

ppm

public double ppm

Bursa Wolf scaling in parts per million.

targetDatum

public final GeodeticDatum targetDatum

The target datum for this parameters.

Constructor Detail

BursaWolfParameters

public BursaWolfParameters(GeodeticDatum target)

Constructs a transformation info with all parameters set to 0.

Parameters:

target - The target datum for this parameters.

Method Detail

isIdentity

public boolean isIdentity()

Returns true if this Bursa Wolf parameters performs no operation. This is true when all parameters are set to zero.

Returns:

true if the parameters describe no operation.

isTranslation

public boolean isTranslation()

Returns true if this Bursa Wolf parameters contains only translation terms.

Returns:

true if the parameters describe to a translation only.

getAffineTransform

public XMatrix getAffineTransform()

Returns an affine transform that can be used to define this Bursa Wolf transformation. The formula is as follows:

S = 1 + ppm/1000000
 ┌    ┐    ┌                            ┐  ┌   ┐
 │ X' │    │     S   -ez*S   +ey*S   dx │  │ X │
 │ Y' │  = │ +ez*S       S   -ex*S   dy │  │ Y │
 │ Z' │    │ -ey*S   +ex*S       S   dz │  │ Z │
 │ 1  │    │     0       0       0    1 │  │ 1 │
 └    ┘    └                            ┘  └   ┘

This affine transform can be applied on geocentric coordinates.

Returns:

An affine transform created from the parameters.

setAffineTransform

public void setAffineTransform(Matrix matrix,
                               double eps)
                        throws IllegalArgumentException

Sets transformation info from the specified matrix, which must be affine. In addition, the matrix minus the last row and last column must be antisymmetric.

Parameters:

matrix - The matrix to fit as a Bursa-Wolf construct.

eps - The tolerance error for the antisymmetric matrix test. Should be a small number like 1E-4.

Throws:

IllegalArgumentException - if the specified matrix doesn't meet the conditions.

Since:

2.2

hashCode

public int hashCode()

Returns a hash value for this object.

Overrides:

hashCode in class Object

Returns:

The hash code value. This value doesn't need to be the same in past or future versions of this class.

clone

public BursaWolfParameters clone()

Returns a copy of this object.

Overrides:

clone in class Object

Returns:

A clone of the parameters.

equals

public boolean equals(Object object)

Compares the specified object with this object for equality.

Overrides:

equals in class Object

Parameters:

object - The object to compare with the parameters.

Returns:

true if the given object is equal to the parameters.

formatWKT

public String formatWKT(Formatter formatter)

Formats the inner part of a Well Known Text (WKT) element. The WKT contains the parameters in translation, rotation, scale order, as in TOWGS84[dx, dy, dz, ex, ey, ez, ppm].

Specified by:

formatWKT in interface Formattable

Overrides:

formatWKT in class FormattableObject

Parameters:

formatter - The formatter to use.

Returns:

The WKT element name, which is "TOWGS84".

See Also:

FormattableObject.toWKT(), FormattableObject.toString()