org.geotools.metadata.math

Class Plane

Object

Plane

All Implemented Interfaces:

Serializable, Cloneable

public class Plane
extends Object
implements Cloneable, Serializable

Equation of a plane in a three-dimensional space (x,y,z). The plane equation is expressed by c, cx and cy coefficients as below:

z(x,y) = c + cx*x + cy*y

Those coefficients can be set directly, or computed by a linear regression of this plane through a set of three-dimensional points.

Since:

2.0

Author:

Martin Desruisseaux (PMO, IRD), Howard Freeland, for algorithmic inspiration

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
double	c The c coefficient for this plane.
double	cx The cx coefficient for this plane.
double	cy The cy coefficient for this plane.

Constructor Summary

Constructors

Constructor and Description
Plane() Construct a new plane.

Method Summary

Modifier and Type	Method and Description
Plane	clone() Returns a clone of this plane.
boolean	equals(Object object) Compares this plane with the specified object for equality.
int	hashCode() Returns a hash code value for this plane.
void	setPlane(double[][] points) Computes the plane's coefficients from the specified points.
void	setPlane(double[] x, double[] y, double[] z) Computes the plane's coefficients from a set of points.
String	toString() Returns a string representation of this plane.
double	x(double y, double z) Computes the x value for the specified (y,z) point.
double	y(double x, double z) Computes the y value for the specified (x,z) point.
double	z(double x, double y) Computes the z value for the specified (x,y) point.

Methods inherited from class Object

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

Field Detail

c

public double c

The c coefficient for this plane. This coefficient appears in the place equation c+cx*x+cy*y.

cx

public double cx

The cx coefficient for this plane. This coefficient appears in the place equation c+cx*x+cy*y.

cy

public double cy

The cy coefficient for this plane. This coefficient appears in the place equation c+cx*x+cy*y.

Constructor Detail

Plane

public Plane()

Construct a new plane. All coefficients are set to 0.

Method Detail

z

public final double z(double x,
                      double y)

Computes the z value for the specified (x,y) point. The z value is computed using the following equation:

z(x,y) = c + cx*x + cy*y

Parameters:

x - The x value.

y - The y value.

Returns:

The z value.

y

public final double y(double x,
                      double z)

Computes the y value for the specified (x,z) point. The y value is computed using the following equation:

y(x,z) = (z - (c+cx*x)) / cy

Parameters:

x - The x value.

z - The y value.

Returns:

The y value.

x

public final double x(double y,
                      double z)

Computes the x value for the specified (y,z) point. The x value is computed using the following equation:

x(y,z) = (z - (c+cy*y)) / cx

Parameters:

y - The x value.

z - The y value.

Returns:

The x value.

setPlane

public void setPlane(double[][] points)
              throws ArithmeticException

Computes the plane's coefficients from the specified points. Three points are enough for determining exactly the plane, providing that the points are not colinear. This method allows points to be provided in Z,Y,Z order:

 double[] P1 = new double[]{ a.getX(), a.getY(), a.getZ() );
 double[] P2 = new double[]{ b.getX(), b.getY(), b.getZ() );
 double[] P3 = new double[]{ c.getX(), c.getY(), c.getZ() );
 plane.setPlane( new double[][]{ P1, P2, P3 } );

Parameters:

points - Array of three points

Throws:

ArithmeticException - If the three points are colinear.

setPlane

public void setPlane(double[] x,
                     double[] y,
                     double[] z)
              throws IllegalArgumentException

Computes the plane's coefficients from a set of points. This method use a linear regression in the least-square sense. Result is undertermined if all points are colinear. This method allows points to be provided as a series of X,Y and Z arrays:

 double[] X = new double[]{ a.getX(), b.getX(), c.getX() );
 double[] Y = new double[]{ a.getX(), b.getX(), c.getX() );
 double[] Z = new double[]{ a.getZ(), b.getZ(), c.getZ() );
 plane.setPlane( X, Y, Z  );

Parameters:

x - vector of x coordinates

y - vector of y coordinates

z - vector of z values

Throws:

MismatchedSizeException - if x, y and z don't have the same length.

IllegalArgumentException

toString

public String toString()

Returns a string representation of this plane. The string will contains the plane's equation, as below:

z(x,y) = c + cx*x + cy*y

Overrides:

toString in class Object

equals

public boolean equals(Object object)

Compares this plane with the specified object for equality.

Overrides:

equals in class Object

hashCode

public int hashCode()

Returns a hash code value for this plane.

Overrides:

hashCode in class Object

clone

public Plane clone()

Returns a clone of this plane.

Overrides:

clone in class Object

Returns:

A copy of this object.

See Also:

Object.clone()