org.geotoolkit.geometry
Class DirectPosition2D

Object
  Point2D
      Point2D.Double
          DirectPosition2D

All Implemented Interfaces:

Serializable, Cloneable, Position, DirectPosition

public class DirectPosition2D
extends Point2D.Double
implements DirectPosition, Serializable, Cloneable

Holds the coordinates for a two-dimensional position within some coordinate reference system. This class inherits x and y fields. But despite their names, they don't need to be oriented toward East and North. The (x,y) axis can have any orientation and should be understood as "ordinate 0" and "ordinate 1" values instead. This is not specific to this implementation; in Java2D too, the visual axis orientation depend on the affine transform in the graphics context.

The rational for avoiding axis orientation restriction is that other DirectPosition implementation do not have such restriction, and it would be hard to generalize. For example there is no clear "x" or "y" classification for North-East direction.

Caution when used in collections
Do not mix instances of this class with ordinary Point2D instances in a HashSet or as HashMap keys. It is not possible to meet both Point2D.hashCode() and DirectPosition.hashCode() contract, and this class chooses to implements the later. Consequently, hashCode() is inconsistent with Point2D.equals(java.lang.Object) but is consistent with DirectPosition.equals(java.lang.Object).

In other words, it is safe to add instances of DirectPosition2D in a HashSet<DirectPosition>, but it is unsafe to add them in a HashSet<Point2D>. Collections that do not rely on Object.hashCode(), like ArrayList, are safe in all cases.

Since:

2.0

Version:

3.09

Author:

Martin Desruisseaux (IRD, Geomatys)

See Also:

DirectPosition1D, GeneralDirectPosition, Point2D, Serialized Form

Module:

referencing/geotk-referencing (download)

View source code for this class

Nested Class Summary

Nested classes/interfaces inherited from class Point2D

Point2D.Double, Point2D.Float

Field Summary

Fields inherited from class Point2D.Double

x, y

Constructor Summary

DirectPosition2D()
Constructs a position initialized to (0,0) with a null coordinate reference system.

DirectPosition2D(CoordinateReferenceSystem crs)
Constructs a position with the specified coordinate reference system.

DirectPosition2D(CoordinateReferenceSystem crs, double x, double y)
Constructs a 2D position from the specified ordinates in the specified CRS.

DirectPosition2D(DirectPosition point)
Constructs a position initialized to the same values than the specified point.

DirectPosition2D(double x, double y)
Constructs a 2D position from the specified ordinates.

DirectPosition2D(Point2D point)
Constructs a position from the specified Point2D.

DirectPosition2D(String wkt)
Constructs a position initialized to the values parsed from the given string in Well Known Text (WKT) format.

Method Summary

DirectPosition2D	clone() Returns a clone of this point.
boolean	equals(Object object) Compares this point with the specified object for equality.
double[]	getCoordinate() Returns a sequence of numbers that hold the coordinate of this position in its reference system.
CoordinateReferenceSystem	getCoordinateReferenceSystem() Returns the coordinate reference system in which the coordinate is given.
int	getDimension() The length of coordinate sequence (the number of entries).
DirectPosition	getDirectPosition() Returns always this, the direct position for this position.
double	getOrdinate(int dimension) Returns the ordinate at the specified dimension.
int	hashCode() Returns a hash value for this coordinate.
void	setCoordinateReferenceSystem(CoordinateReferenceSystem crs) Sets the coordinate reference system in which the coordinate is given.
void	setLocation(DirectPosition position) Sets this coordinate to the specified direct position.
void	setOrdinate(int dimension, double value) Sets the ordinate value along the specified dimension.
Point2D	toPoint2D() Returns a Point2D with the same coordinate as this direct position.
String	toString() Formats this position in the Well Known Text (WKT) format.

Methods inherited from class Point2D.Double

getX, getY, setLocation

Methods inherited from class Point2D

distance, distance, distance, distanceSq, distanceSq, distanceSq, setLocation

Methods inherited from class Object

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

Constructor Detail

DirectPosition2D

public DirectPosition2D()

Constructs a position initialized to (0,0) with a null coordinate reference system.

DirectPosition2D

public DirectPosition2D(CoordinateReferenceSystem crs)

Constructs a position with the specified coordinate reference system.

Parameters:

crs - The coordinate reference system, or null.

DirectPosition2D

public DirectPosition2D(double x,
                        double y)

Constructs a 2D position from the specified ordinates. Despite their name, the (x,y) coordinates don't need to be oriented toward (East, North). Those parameter names simply match the x and y fields. See the class javadoc for details.

Parameters:

x - The x value.

y - The y value.

DirectPosition2D

public DirectPosition2D(CoordinateReferenceSystem crs,
                        double x,
                        double y)

Constructs a 2D position from the specified ordinates in the specified CRS. Despite their name, the (x,y) coordinates don't need to be oriented toward (East, North). Those parameter names simply match the x and y fields. The actual axis orientations are determined by the specified CRS. See the class javadoc for details.

Parameters:

crs - The coordinate reference system, or null.

x - The x value.

y - The y value.

DirectPosition2D

public DirectPosition2D(Point2D point)

Constructs a position from the specified Point2D.

Parameters:

point - The point to copy.

DirectPosition2D

public DirectPosition2D(DirectPosition point)

Constructs a position initialized to the same values than the specified point.

Parameters:

point - The point to copy.

DirectPosition2D

public DirectPosition2D(String wkt)
                 throws NumberFormatException,
                        IllegalArgumentException

Constructs a position initialized to the values parsed from the given string in Well Known Text (WKT) format. The given string is typically a POINT element like below:

POINT(6 10)

Parameters:

wkt - The POINT or other kind of element to parse.

Throws:

NumberFormatException - If a number can not be parsed.

IllegalArgumentException - If the parenthesis are not balanced.

MismatchedDimensionException - If the given point is not two-dimensional.

Since:

3.09

See Also:

AbstractDirectPosition.toString(DirectPosition), CoordinateFormat

Method Detail

getDirectPosition

public DirectPosition getDirectPosition()

Returns always this, the direct position for this position.

Specified by:

getDirectPosition in interface Position

Since:

2.5

getCoordinateReferenceSystem

public final CoordinateReferenceSystem getCoordinateReferenceSystem()

Returns the coordinate reference system in which the coordinate is given. May be null if this particular DirectPosition is included in a larger object with such a reference to a CRS.

Specified by:

getCoordinateReferenceSystem in interface DirectPosition

Returns:

The coordinate reference system, or null.

setCoordinateReferenceSystem

public void setCoordinateReferenceSystem(CoordinateReferenceSystem crs)

Sets the coordinate reference system in which the coordinate is given.

Parameters:

crs - The new coordinate reference system, or null.

getDimension

public final int getDimension()

The length of coordinate sequence (the number of entries). This is always 2 for DirectPosition2D objects.

Specified by:

getDimension in interface DirectPosition

Returns:

The dimensionality of this position.

getCoordinate

public double[] getCoordinate()

Returns a sequence of numbers that hold the coordinate of this position in its reference system.

Specified by:

getCoordinate in interface DirectPosition

Returns:

The coordinate.

getOrdinate

public final double getOrdinate(int dimension)
                         throws IndexOutOfBoundsException

Returns the ordinate at the specified dimension.

Specified by:

getOrdinate in interface DirectPosition

Parameters:

dimension - The dimension in the range 0 to 1 inclusive.

Returns:

The coordinate at the specified dimension.

Throws:

IndexOutOfBoundsException - if the specified dimension is out of bounds.

TODO:

Provides a more detailled error message.

setOrdinate

public final void setOrdinate(int dimension,
                              double value)
                       throws IndexOutOfBoundsException

Sets the ordinate value along the specified dimension.

Specified by:

setOrdinate in interface DirectPosition

Parameters:

dimension - the dimension for the ordinate of interest.

value - the ordinate value of interest.

Throws:

IndexOutOfBoundsException - if the specified dimension is out of bounds.

setLocation

public void setLocation(DirectPosition position)
                 throws MismatchedDimensionException

Sets this coordinate to the specified direct position. If the specified position contains a coordinate reference system, then the CRS for this position will be set to the CRS of the specified position.

Parameters:

position - The new position for this point.

Throws:

MismatchedDimensionException - if this point doesn't have the expected dimension.

toPoint2D

public Point2D toPoint2D()

Returns a Point2D with the same coordinate as this direct position.

Returns:

This position as a point.

toString

public String toString()

Formats this position in the Well Known Text (WKT) format. The output is like below:

POINT(ordinates)

The output of this method can be parsed by the GeneralDirectPosition constructor.

Overrides:

toString in class Point2D.Double

hashCode

public int hashCode()

Returns a hash value for this coordinate. This method implements the DirectPosition.hashCode() contract, not the Point2D.hashCode() contract.

Specified by:

hashCode in interface DirectPosition

Overrides:

hashCode in class Point2D

Returns:

A hash code value for this position.

equals

public boolean equals(Object object)

Compares this point with the specified object for equality. If the given object implements the DirectPosition interface, then the comparison is performed as specified in its DirectPosition.equals(java.lang.Object) contract. Otherwise the comparison is performed as specified in Point2D.equals(java.lang.Object).

Specified by:

equals in interface DirectPosition

Overrides:

equals in class Point2D

Parameters:

object - The object to compare with this position.

Returns:

true if the given object is equal to this position.

clone

public DirectPosition2D clone()

Returns a clone of this point.

Overrides:

clone in class Point2D

Returns:

A clone of this position.