Package org.geotools.geometry

Class Position2D

Object
Point2D
Point2D.Double
Position2D
All Implemented Interfaces:
Serializable, Cloneable, Position, Cloneable
public class Position2D extends Point2D.Double implements Position, Serializable, Cloneable
Holds the coordinates for a two-dimensional position within some coordinate reference system.

Note 1:

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 Position implementation do not have such restriction, and it would be hard to generalize (what to do with North-East direction?).

Note 2:

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 Position.hashCode() contract, and this class choose to implements the later. Concequently, hashCode() is inconsistent with Point2D.equals(java.lang.Object) (but is consistent with Position.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
Author:
Martin Desruisseaux (IRD)
See Also:

  • Constructor Details

    • Position2D

      public Position2D()
      Constructs a position initialized to (0,0) with a null coordinate reference system.

    • Position2D

      public Position2D(CoordinateReferenceSystem crs)
      Constructs a position with the specified coordinate reference system.
      Parameters:
      crs - The coordinate reference system, or null.

    • Position2D

      public Position2D(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.

    • Position2D

      public Position2D(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.

    • Position2D

      public Position2D(Point2D point)
      Constructs a position from the specified Point2D.
      Parameters:
      point - The point to copy.

    • Position2D

      public Position2D(Position point)
      Constructs a position initialized to the same values than the specified point.
      Parameters:
      point - The point to copy.

  • Method Details

    • getDirectPosition

      public Position getDirectPosition()
      Returns always this, the direct position for this position.
      Specified by:
      getDirectPosition in interface Position
      Returns:
      The direct position (may be this).
      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 coordinate reference system.
      Specified by:
      getCoordinateReferenceSystem in interface Position
      Returns:
      The coordinate reference system, or null.

    • setCoordinateReferenceSystem

      public void setCoordinateReferenceSystem(CoordinateReferenceSystem crs)
      Set 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 Position
      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 Position
      Returns:
      The coordinates

    • getOrdinate

      public final double getOrdinate(int dimension) throws IndexOutOfBoundsException
      Returns the ordinate at the specified dimension.
      Specified by:
      getOrdinate in interface Position
      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.

    • setOrdinate

      public final void setOrdinate(int dimension, double value) throws IndexOutOfBoundsException
      Sets the ordinate value along the specified dimension.
      Specified by:
      setOrdinate in interface Position
      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(Position position) throws MismatchedDimensionException
      Set 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()
      Returns a string representation of this coordinate. The default implementation formats this coordinate using a shared instance of CoordinateFormat. This is okay for occasional formatting (for example for debugging purpose). But if there is a lot of positions to format, users will get better performance and more control by using their own instance of CoordinateFormat.
      Overrides:
      toString in class Point2D.Double

    • hashCode

      public int hashCode()
      Returns a hash value for this coordinate. This method implements the Position.hashCode() contract, not the Point2D.hashCode() contract.
      Specified by:
      hashCode in interface Position
      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 Position interface, then the comparaison is performed as specified in its Position.equals(java.lang.Object) contract. Otherwise the comparaison is performed as specified in Point2D.equals(java.lang.Object).
      Specified by:
      equals in interface Position
      Overrides:
      equals in class Point2D
      Parameters:
      object - The object to compare with this position.
      Returns:
      true if the given object is equals to this position.

    • clone

      public Position2D clone()
      Returns a clone of this point.
      Specified by:
      clone in interface Cloneable
      Overrides:
      clone in class Point2D
      Returns:
      A clone of this position.
      See Also: