S2Point (Apache Commons Math 3.6.1 API)

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:
Serialized Form

Field Summary

Fields
Modifier and Type	Field and 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.
`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: \( \theta = any angle, \varphi = 0 \)).

Constructor Summary

Constructors
Constructor and Description

S2Point(double theta, double phi)
Simple constructor.

S2Point(Vector3D vector)
Simple constructor.

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

Method Summary

Methods
Modifier and Type	Method and 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 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.
- 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
- Method Detail
  - 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(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

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

Constructor Detail

S2Point

S2Point

Method Detail

getTheta

getPhi

getVector

getSpace

isNaN

negate

distance

distance

equals

hashCode