java.lang.Object
- org.apache.commons.math3.geometry.spherical.twod.S2Point

All Implemented Interfaces:

java.io.Serializable, Point<Sphere2D>
```
public class S2Point
extends java.lang.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:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`static S2Point`	`MINUS_I`	-I (coordinates: \( \theta = \pi, \varphi = \pi/2 \)).
`static S2Point`	`MINUS_J`	-J (coordinates: \( \theta = 3\pi/2, \varphi = \pi/2 \)).
`static S2Point`	`MINUS_K`	-K (coordinates: \( \theta = any angle, \varphi = \pi \)).
`static S2Point`	`NaN`	A vector with all coordinates set to NaN.
`private double`	`phi`	Polar angle \( \varphi \).
`static S2Point`	`PLUS_I`	+I (coordinates: \( \theta = 0, \varphi = \pi/2 \)).
`static S2Point`	`PLUS_J`	+J (coordinates: \( \theta = \pi/2, \varphi = \pi/2 \))).
`static S2Point`	`PLUS_K`	+K (coordinates: \( \theta = any angle, \varphi = 0 \)).
`private static long`	`serialVersionUID`	Serializable UID.
`private double`	`theta`	Azimuthal angle \( \theta \) in the x-y plane.
`private Vector3D`	`vector`	Corresponding 3D normalized vector.

Constructor Summary

Constructors
Modifier	Constructor	Description
	`S2Point(double theta, double phi)`	Simple constructor.
`private`	`S2Point(double theta, double phi, Vector3D vector)`	Build a point from its internal components.
	`S2Point(Vector3D vector)`	Simple constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
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(java.lang.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.
`private static Vector3D`	`vector(double theta, double phi)`	Build the normalized vector corresponding to spherical coordinates.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - 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.
  - serialVersionUID
```
private static final long serialVersionUID
```
    Serializable UID.
    
    See Also:
    
    Constant Field Values
  - theta
```
private final double theta
```
    Azimuthal angle \( \theta \) in the x-y plane.
  - phi
```
private final double phi
```
    Polar angle \( \varphi \).
  - vector
```
private final Vector3D vector
```
    Corresponding 3D normalized vector.
- Constructor Detail
  - 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:
    
    getTheta(), getPhi()
  - 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
  - S2Point
```
private S2Point(double theta,
                double phi,
                Vector3D vector)
```
    Build a point from its internal components.
    
    Parameters:
    
    theta - azimuthal angle \( \theta \) in the x-y plane
    
    phi - polar angle \( \varphi \)
    
    vector - corresponding vector
- Method Detail
  - vector
```
private static Vector3D vector(double theta,
                               double phi)
                        throws OutOfRangeException
```
    Build the normalized vector corresponding to spherical coordinates.
    
    Parameters:
    
    theta - azimuthal angle \( \theta \) in the x-y plane
    
    phi - polar angle \( \varphi \)
    
    Returns:
    
    normalized vector
    
    Throws:
    
    OutOfRangeException - if \( \varphi \) is not in the [\( 0; \pi \)] range
  - 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:
    
    S2Point(double, double)
  - getPhi
```
public double getPhi()
```
    Get the polar angle \( \varphi \).
    
    Returns:
    
    polar angle \( \varphi \)
    
    See Also:
    
    S2Point(double, double)
  - 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(java.lang.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 java.lang.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 java.lang.Object
    
    Returns:
    
    a hash code value for this object

Class S2Point

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PLUS_I

PLUS_J

PLUS_K

MINUS_I

MINUS_J

MINUS_K

NaN

serialVersionUID

theta

phi

vector

Constructor Detail

S2Point

S2Point

S2Point

Method Detail

vector

getTheta

getPhi

getVector

getSpace

isNaN

negate

distance

distance

equals

hashCode