Package org.apache.commons.math3.geometry.spherical.twod

Class S2Point

java.lang.Object
org.apache.commons.math3.geometry.spherical.twod.S2Point
All Implemented Interfaces:
Serializable, Point<Sphere2D>
public class S2Point extends Object implements Point<Sphere2D>
This class represents a point on the 2-sphere.

We use the mathematical convention to use the azimuthal angle \( \theta \) in the x-y plane as the first coordinate, and the polar angle \( \varphi \) as the second coordinate (see Spherical Coordinates in MathWorld).

Instances of this class are guaranteed to be immutable.

Since:
3.3
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final S2Point
    MINUS_I
    -I (coordinates: \( \theta = \pi, \varphi = \pi/2 \)).
    static final S2Point
    MINUS_J
    -J (coordinates: \( \theta = 3\pi/2, \varphi = \pi/2 \)).
    static final S2Point
    MINUS_K
    -K (coordinates: \( \theta = any angle, \varphi = \pi \)).
    static final S2Point
    NaN
    A vector with all coordinates set to NaN.
    static final S2Point
    PLUS_I
    +I (coordinates: \( \theta = 0, \varphi = \pi/2 \)).
    static final S2Point
    PLUS_J
    +J (coordinates: \( \theta = \pi/2, \varphi = \pi/2 \))).
    static final S2Point
    PLUS_K
    +K (coordinates: \( \theta = any angle, \varphi = 0 \)).

  • Constructor Summary

    Constructors
    Constructor
    Description
    S2Point(double theta, double phi)
    Simple constructor.
    S2Point(Vector3D vector)
    Simple constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    double
    distance(Point<Sphere2D> point)
    Compute the distance between the instance and another point.
    static double
    distance(S2Point p1, S2Point p2)
    Compute the distance (angular separation) between two points.
    boolean
    equals(Object other)
    Test for the equality of two points on the 2-sphere.
    double
    getPhi()
    Get the polar angle \( \varphi \).
    Space
    getSpace()
    Get the space to which the point belongs.
    double
    getTheta()
    Get the azimuthal angle \( \theta \) in the x-y plane.
    Vector3D
    getVector()
    Get the corresponding normalized vector in the 3D euclidean space.
    int
    hashCode()
    Get a hashCode for the 2D vector.
    boolean
    isNaN()
    Returns true if any coordinate of this point is NaN; false otherwise
    S2Point
    negate()
    Get the opposite of the instance.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • PLUS_I

      public static final S2Point PLUS_I
      +I (coordinates: \( \theta = 0, \varphi = \pi/2 \)).

    • PLUS_J

      public static final S2Point PLUS_J
      +J (coordinates: \( \theta = \pi/2, \varphi = \pi/2 \))).

    • PLUS_K

      public static final S2Point PLUS_K
      +K (coordinates: \( \theta = any angle, \varphi = 0 \)).

    • MINUS_I

      public static final S2Point MINUS_I
      -I (coordinates: \( \theta = \pi, \varphi = \pi/2 \)).

    • MINUS_J

      public static final S2Point MINUS_J
      -J (coordinates: \( \theta = 3\pi/2, \varphi = \pi/2 \)).

    • MINUS_K

      public static final S2Point MINUS_K
      -K (coordinates: \( \theta = any angle, \varphi = \pi \)).

    • NaN

      public static final S2Point NaN
      A vector with all coordinates set to NaN.

  • Constructor Details

    • S2Point

      public S2Point(double theta, double phi) throws OutOfRangeException
      Simple constructor. Build a vector from its spherical coordinates
      Parameters:
      theta - azimuthal angle \( \theta \) in the x-y plane
      phi - polar angle \( \varphi \)
      Throws:
      OutOfRangeException - if \( \varphi \) is not in the [\( 0; \pi \)] range
      See Also:

    • S2Point

      public S2Point(Vector3D vector) throws MathArithmeticException
      Simple constructor. Build a vector from its underlying 3D vector
      Parameters:
      vector - 3D vector
      Throws:
      MathArithmeticException - if vector norm is zero

  • Method Details

    • getTheta

      public double getTheta()
      Get the azimuthal angle \( \theta \) in the x-y plane.
      Returns:
      azimuthal angle \( \theta \) in the x-y plane
      See Also:

    • getPhi

      public double getPhi()
      Get the polar angle \( \varphi \).
      Returns:
      polar angle \( \varphi \)
      See Also:

    • getVector

      public Vector3D getVector()
      Get the corresponding normalized vector in the 3D euclidean space.
      Returns:
      normalized vector

    • getSpace

      public Space getSpace()
      Get the space to which the point belongs.
      Specified by:
      getSpace in interface Point<Sphere2D>
      Returns:
      containing space

    • isNaN

      public boolean isNaN()
      Returns true if any coordinate of this point is NaN; false otherwise
      Specified by:
      isNaN in interface Point<Sphere2D>
      Returns:
      true if any coordinate of this point is NaN; false otherwise

    • negate

      public S2Point negate()
      Get the opposite of the instance.
      Returns:
      a new vector which is opposite to the instance

    • distance

      public double distance(Point<Sphere2D> point)
      Compute the distance between the instance and another point.
      Specified by:
      distance in interface Point<Sphere2D>
      Parameters:
      point - second point
      Returns:
      the distance between the instance and p

    • distance

      public static double distance(S2Point p1, S2Point p2)
      Compute the distance (angular separation) between two points.
      Parameters:
      p1 - first vector
      p2 - second vector
      Returns:
      the angular separation between p1 and p2

    • equals

      public boolean equals(Object other)
      Test for the equality of two points on the 2-sphere.

      If all coordinates of two points are exactly the same, and none are Double.NaN, the two points are considered to be equal.

      NaN coordinates are considered to affect globally the vector and be equals to each other - i.e, if either (or all) coordinates of the 2D vector are equal to Double.NaN, the 2D vector is equal to NaN.

      Overrides:
      equals in class Object
      Parameters:
      other - Object to test for equality to this
      Returns:
      true if two points on the 2-sphere objects are equal, false if object is null, not an instance of S2Point, or not equal to this S2Point instance

    • hashCode

      public int hashCode()
      Get a hashCode for the 2D vector.

      All NaN values have the same hash code.

      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this object