org.deegree_impl.model.ct
Class GeocentricTransform

java.lang.Object
  org.deegree_impl.model.ct.AbstractMathTransform
      org.deegree_impl.model.ct.GeocentricTransform

All Implemented Interfaces:

MathTransform, java.io.Serializable

class GeocentricTransform

extends AbstractMathTransform

implements java.io.Serializable

Transforms three dimensional geographic points to geocentric coordinate points. Input points must be longitudes, latitudes and heights above the ellipsoid.

Version:

1.00

Author:

Frank Warmerdam, Martin Desruisseaux

Nested Class Summary

private class	GeocentricTransform.Inverse Inverse of a geocentric transform.
(package private) static class	GeocentricTransform.Provider The provider for GeocentricTransform.

Field Summary

private double	a Semi-major axis of ellipsoid in meters.
private double	a2 Square of semi-major axis (@link #a}²).
private static double	AD_C Toms region 1 constant.
private double	b Semi-minor axis of ellipsoid in meters.
private double	b2 Square of semi-minor axis (b²).
private static double	COS_67P5 Cosine of 67.5 degrees.
private double	e2 Eccentricity squared.
private double	ep2 2nd eccentricity squared.
private boolean	hasHeight true if geographic coordinates include an ellipsoidal height (i.e. are 3-D), or false if they are strictly 2-D.
private MathTransform	inverse The inverse of this transform.
private static double	MAX_ERROR Maximal error tolerance in metres during // assertions, in metres.
private static long	serialVersionUID Serial number for interoperability with different versions.

Constructor Summary

protected	GeocentricTransform(double semiMajor, double semiMinor, Unit units, boolean hasHeight) Construct a transform.
protected	GeocentricTransform(Ellipsoid ellipsoid, boolean hasHeight) Construct a transform.

Method Summary

private static void	checkArgument(java.lang.String name, double value, double max) Check an argument value.
private double	checkTransform(double[] points) Transform the last half if the specified array and returns the distance with the first half.
boolean	equals(java.lang.Object object) Compares the specified object with this math transform for equality.
int	getDimSource() Gets the dimension of input points, which is 2 or 3.
int	getDimTarget() Gets the dimension of output points, which is 3.
int	hashCode() Returns a hash value for this transform.
MathTransform	inverse() Returns the inverse of this transform.
protected void	inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Converts geocentric coordinates (x, y, z) to geodetic coordinates (longitude, latitude, height), according to the current ellipsoid parameters.
protected void	inverseTransform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Converts geocentric coordinates (x, y, z) to geodetic coordinates (longitude, latitude, height), according to the current ellipsoid parameters.
boolean	isIdentity() Tests whether this transform does not move any points.
java.lang.String	toString() Returns the WKT for this math transform.
(package private) java.lang.String	toString(java.lang.String classification) Returns the WKT for this math transform with the specified classification name.
void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Converts geodetic coordinates (longitude, latitude, height) to geocentric coordinates (x, y, z) according to the current ellipsoid parameters.
private void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts, boolean hasHeight) Implementation of geodetic to geocentric conversion.
void	transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Converts geodetic coordinates (longitude, latitude, height) to geocentric coordinates (x, y, z) according to the current ellipsoid parameters.

Methods inherited from class org.deegree_impl.model.ct.AbstractMathTransform

addParameter, addParameter, createTransformedShape, createTransformedShape, derivative, derivative, getName, paramMT, toOpenGIS, transform, transform

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

Serial number for interoperability with different versions.

See Also:

Constant Field Values

MAX_ERROR

private static final double MAX_ERROR

Maximal error tolerance in metres during // assertions, in metres. If // assertions are enabled (JDK 1.4 only), then every coordinates transformed with inverseTransform(double[], int, double[], int, int) will be transformed again with transform(double[], int, double[], int, int). If the distance between the resulting position and the original position is greater than MAX_ERROR, then a // assertionError is thrown.

See Also:

Constant Field Values

COS_67P5

private static final double COS_67P5

Cosine of 67.5 degrees.

See Also:

Constant Field Values

AD_C

private static final double AD_C

Toms region 1 constant.

See Also:

Constant Field Values

a

private final double a

Semi-major axis of ellipsoid in meters.

b

private final double b

Semi-minor axis of ellipsoid in meters.

a2

private final double a2

Square of semi-major axis (@link #a}²).

b2

private final double b2

Square of semi-minor axis (b²).

e2

private final double e2

Eccentricity squared.

ep2

private final double ep2

2nd eccentricity squared.

hasHeight

private final boolean hasHeight

true if geographic coordinates include an ellipsoidal height (i.e. are 3-D), or false if they are strictly 2-D.

inverse

private transient MathTransform inverse

The inverse of this transform. Will be created only when needed.

Constructor Detail

GeocentricTransform

protected GeocentricTransform(Ellipsoid ellipsoid,
                              boolean hasHeight)

Construct a transform.

Parameters:

ellipsoid - The ellipsoid.

hasHeight - true if geographic coordinates include an ellipsoidal height (i.e. are 3-D), or false if they are strictly 2-D.

GeocentricTransform

protected GeocentricTransform(double semiMajor,
                              double semiMinor,
                              Unit units,
                              boolean hasHeight)

Construct a transform.

Parameters:

semiMajor - The semi-major axis length.

semiMinor - The semi-minor axis length.

units - The axis units.

hasHeight - true if geographic coordinates include an ellipsoidal height (i.e. are 3-D), or false if they are strictly 2-D.

Method Detail

checkArgument

private static void checkArgument(java.lang.String name,
                                  double value,
                                  double max)
                           throws java.lang.IllegalArgumentException

Check an argument value. The argument must be greater than 0 and finite, otherwise an exception is thrown.

Parameters:

name - The argument name.

value - The argument value.

max - The maximal legal argument value.

Throws:

java.lang.IllegalArgumentException

transform

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

Converts geodetic coordinates (longitude, latitude, height) to geocentric coordinates (x, y, z) according to the current ellipsoid parameters.

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.

transform

private void transform(double[] srcPts,
                       int srcOff,
                       double[] dstPts,
                       int dstOff,
                       int numPts,
                       boolean hasHeight)

Implementation of geodetic to geocentric conversion. This implementation allows the caller to use height in computation.

transform

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

Converts geodetic coordinates (longitude, latitude, height) to geocentric coordinates (x, y, z) according to the current ellipsoid parameters.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

inverseTransform

protected final void inverseTransform(double[] srcPts,
                                      int srcOff,
                                      double[] dstPts,
                                      int dstOff,
                                      int numPts)

Converts geocentric coordinates (x, y, z) to geodetic coordinates (longitude, latitude, height), according to the current ellipsoid parameters. The method used here is derived from "An Improved Algorithm for Geocentric to Geodetic Coordinate Conversion", by Ralph Toms, Feb 1996.

inverseTransform

protected final void inverseTransform(float[] srcPts,
                                      int srcOff,
                                      float[] dstPts,
                                      int dstOff,
                                      int numPts)

Converts geocentric coordinates (x, y, z) to geodetic coordinates (longitude, latitude, height), according to the current ellipsoid parameters. The method used here is derived from "An Improved Algorithm for Geocentric to Geodetic Coordinate Conversion", by Ralph Toms, Feb 1996.

checkTransform

private double checkTransform(double[] points)

Transform the last half if the specified array and returns the distance with the first half. Array points must have a length of 6.

getDimSource

public int getDimSource()

Gets the dimension of input points, which is 2 or 3.

Specified by:

getDimSource in interface MathTransform

See Also:

CT_MathTransform.getDimSource()

getDimTarget

public final int getDimTarget()

Gets the dimension of output points, which is 3.

Specified by:

getDimTarget in interface MathTransform

See Also:

CT_MathTransform.getDimTarget()

isIdentity

public final boolean isIdentity()

Tests whether this transform does not move any points. This method returns always false.

Specified by:

isIdentity in interface MathTransform

Returns:

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

inverse

public MathTransform inverse()

Returns the inverse of this transform.

Specified by:

inverse in interface MathTransform

Overrides:

inverse in class AbstractMathTransform

hashCode

public final int hashCode()

Returns a hash value for this transform.

Overrides:

hashCode in class AbstractMathTransform

equals

public final boolean equals(java.lang.Object object)

Compares the specified object with this math transform for equality.

Overrides:

equals in class AbstractMathTransform

toString

public final java.lang.String toString()

Returns the WKT for this math transform.

Overrides:

toString in class AbstractMathTransform

toString

final java.lang.String toString(java.lang.String classification)

Returns the WKT for this math transform with the specified classification name. The classification name should be "Ellipsoid_To_Geocentric" or "Geocentric_To_Ellipsoid".