java.lang.Object
- org.hipparchus.geometry.spherical.twod.Circle

All Implemented Interfaces:

Embedding<Sphere2D,Sphere1D>, Hyperplane<Sphere2D>
```
public class Circle
extends Object
implements Hyperplane<Sphere2D>, Embedding<Sphere2D,Sphere1D>
```
This class represents an oriented great circle on the 2-sphere.
An oriented circle can be defined by a center point. The circle is the the set of points that are in the normal plan the center.

Since it is oriented the two spherical caps at its two sides are unambiguously identified as a left cap and a right cap. This can be used to identify the interior and the exterior in a simple way by local properties only when part of a line is used to define part of a spherical polygon boundary.

Constructor Summary

Constructors
Constructor	Description
`Circle(Vector3D pole, double tolerance)`	Build a great circle from its pole.
`Circle(Circle circle)`	Copy constructor.
`Circle(S2Point first, S2Point second, double tolerance)`	Build a great circle from two non-aligned points.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Circle`	`copySelf()`	Copy the instance.
`SubCircle`	`emptyHyperplane()`	Build a sub-hyperplane covering nothing.
`Arc`	`getArc(S2Point a, S2Point b)`	Get the arc on this circle between two defining points.
`Arc`	`getInsideArc(Circle other)`	Get the arc of the instance that lies inside the other circle.
`double`	`getOffset(Vector3D direction)`	Get the offset (oriented distance) of a direction.
`double`	`getOffset(Point<Sphere2D> point)`	Get the offset (oriented distance) of a point.
`double`	`getPhase(Vector3D direction)`	Get the phase angle of a direction.
`Vector3D`	`getPointAt(double alpha)`	Get a circle point from its phase around the circle.
`Vector3D`	`getPole()`	Get the pole of the circle.
`Circle`	`getReverse()`	Get the reverse of the instance.
`double`	`getTolerance()`	Get the tolerance below which points are considered to belong to the hyperplane.
`static Transform<Sphere2D,Sphere1D>`	`getTransform(Rotation rotation)`	Get a `Transform` embedding a 3D rotation.
`Vector3D`	`getXAxis()`	Get the X axis of the circle.
`Vector3D`	`getYAxis()`	Get the Y axis of the circle.
`Point<Sphere2D>`	`project(Point<Sphere2D> point)`	Project a point to the hyperplane.
`void`	`reset(Vector3D newPole)`	Reset the instance as if built from a pole.
`void`	`revertSelf()`	Revert the instance.
`boolean`	`sameOrientationAs(Hyperplane<Sphere2D> other)`	Check if the instance has the same orientation as another hyperplane.
`S2Point`	`toSpace(Point<Sphere1D> point)`	Transform a sub-space point into a space point.
`S1Point`	`toSubSpace(Point<Sphere2D> point)`	Transform a space point into a sub-space point.
`SubCircle`	`wholeHyperplane()`	Build a sub-hyperplane covering the whole hyperplane.
`SphericalPolygonsSet`	`wholeSpace()`	Build a region covering the whole space.

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

- Constructor Detail
  - Circle
```
public Circle(Vector3D pole,
              double tolerance)
       throws MathIllegalArgumentException
```
    Build a great circle from its pole.
    The circle is oriented in the trigonometric direction around pole.
    
    Parameters:
    
    pole - circle pole
    
    tolerance - tolerance below which close sub-arcs are merged together
    
    Throws:
    
    MathIllegalArgumentException - if tolerance is smaller than Sphere1D.SMALLEST_TOLERANCE
  - Circle
```
public Circle(S2Point first,
              S2Point second,
              double tolerance)
       throws MathIllegalArgumentException
```
    Build a great circle from two non-aligned points.
    The circle is oriented from first to second point using the path smaller than \( \pi \).
    
    Parameters:
    
    first - first point contained in the great circle
    
    second - second point contained in the great circle
    
    tolerance - tolerance below which close sub-arcs are merged together
    
    Throws:
    
    MathIllegalArgumentException - if tolerance is smaller than Sphere1D.SMALLEST_TOLERANCE
  - Circle
```
public Circle(Circle circle)
```
    Copy constructor.
    The created instance is completely independent from the original instance, it is a deep copy.
    
    Parameters:
    
    circle - circle to copy
- Method Detail
  - copySelf
```
public Circle copySelf()
```
    Copy the instance.
    The instance created is completely independant of the original one. A deep copy is used, none of the underlying objects are shared (except for immutable objects).
    
    Specified by:
    
    copySelf in interface Hyperplane<Sphere2D>
    
    Returns:
    
    a new hyperplane, copy of the instance
  - reset
```
public void reset(Vector3D newPole)
```
    Reset the instance as if built from a pole.
    The circle is oriented in the trigonometric direction around pole.
    
    Parameters:
    
    newPole - circle pole
  - revertSelf
```
public void revertSelf()
```
    Revert the instance.
  - getReverse
```
public Circle getReverse()
```
    Get the reverse of the instance.
    Get a circle with reversed orientation with respect to the instance. A new object is built, the instance is untouched.
    
    Returns:
    
    a new circle, with orientation opposite to the instance orientation
  - project
```
public Point<Sphere2D> project(Point<Sphere2D> point)
```
    Project a point to the hyperplane.
    
    Specified by:
    
    project in interface Hyperplane<Sphere2D>
    
    Parameters:
    
    point - point to project
    
    Returns:
    
    projected point
  - getTolerance
```
public double getTolerance()
```
    Get the tolerance below which points are considered to belong to the hyperplane.
    
    Specified by:
    
    getTolerance in interface Hyperplane<Sphere2D>
    
    Returns:
    
    tolerance below which points are considered to belong to the hyperplane
  - toSubSpace
```
public S1Point toSubSpace(Point<Sphere2D> point)
```
    Transform a space point into a sub-space point.
    
    Specified by:
    
    toSubSpace in interface Embedding<Sphere2D,Sphere1D>
    
    Parameters:
    
    point - n-dimension point of the space
    
    Returns:
    
    (n-1)-dimension point of the sub-space corresponding to the specified space point
    
    See Also:
    
    getPhase(Vector3D)
  - getPhase
```
public double getPhase(Vector3D direction)
```
    Get the phase angle of a direction.
    The direction may not belong to the circle as the phase is computed for the meridian plane between the circle pole and the direction.
    
    Parameters:
    
    direction - direction for which phase is requested
    
    Returns:
    
    phase angle of the direction around the circle
    
    See Also:
    
    toSubSpace(Point)
  - toSpace
```
public S2Point toSpace(Point<Sphere1D> point)
```
    Transform a sub-space point into a space point.
    
    Specified by:
    
    toSpace in interface Embedding<Sphere2D,Sphere1D>
    
    Parameters:
    
    point - (n-1)-dimension point of the sub-space
    
    Returns:
    
    n-dimension point of the space corresponding to the specified sub-space point
    
    See Also:
    
    getPointAt(double)
  - getPointAt
```
public Vector3D getPointAt(double alpha)
```
    Get a circle point from its phase around the circle.
    
    Parameters:
    
    alpha - phase around the circle
    
    Returns:
    
    circle point on the sphere
    
    See Also:
    
    toSpace(Point), getXAxis(), getYAxis()
  - getXAxis
```
public Vector3D getXAxis()
```
    Get the X axis of the circle.
    This method returns the same value as getPointAt(0.0) but it does not do any computation and always return the same instance.
    
    Returns:
    
    an arbitrary x axis on the circle
    
    See Also:
    
    getPointAt(double), getYAxis(), getPole()
  - getYAxis
```
public Vector3D getYAxis()
```
    Get the Y axis of the circle.
    This method returns the same value as getPointAt(0.5 * FastMath.PI) but it does not do any computation and always return the same instance.
    
    Returns:
    
    an arbitrary y axis point on the circle
    
    See Also:
    
    getPointAt(double), getXAxis(), getPole()
  - getPole
```
public Vector3D getPole()
```
    Get the pole of the circle.
    As the circle is a great circle, the pole does not belong to it.
    
    Returns:
    
    pole of the circle
    
    See Also:
    
    getXAxis(), getYAxis()
  - getInsideArc
```
public Arc getInsideArc(Circle other)
```
    Get the arc of the instance that lies inside the other circle.
    
    Parameters:
    
    other - other circle
    
    Returns:
    
    arc of the instance that lies inside the other circle
  - wholeHyperplane
```
public SubCircle wholeHyperplane()
```
    Build a sub-hyperplane covering the whole hyperplane.
    
    Specified by:
    
    wholeHyperplane in interface Hyperplane<Sphere2D>
    
    Returns:
    
    a sub-hyperplane covering the whole hyperplane
  - emptyHyperplane
```
public SubCircle emptyHyperplane()
```
    Build a sub-hyperplane covering nothing.
    
    Specified by:
    
    emptyHyperplane in interface Hyperplane<Sphere2D>
    
    Returns:
    
    a sub-hyperplane covering nothing
  - wholeSpace
```
public SphericalPolygonsSet wholeSpace()
```
    Build a region covering the whole space.
    
    Specified by:
    
    wholeSpace in interface Hyperplane<Sphere2D>
    
    Returns:
    
    a region containing the instance (really a SphericalPolygonsSet instance)
  - getOffset
```
public double getOffset(Point<Sphere2D> point)
```
    Get the offset (oriented distance) of a point.
    The offset is 0 if the point is on the underlying hyperplane, it is positive if the point is on one particular side of the hyperplane, and it is negative if the point is on the other side, according to the hyperplane natural orientation.
    
    Specified by:
    
    getOffset in interface Hyperplane<Sphere2D>
    
    Parameters:
    
    point - point to check
    
    Returns:
    
    offset of the point
    
    See Also:
    
    getOffset(Vector3D)
  - getOffset
```
public double getOffset(Vector3D direction)
```
    Get the offset (oriented distance) of a direction.
    The offset is defined as the angular distance between the circle center and the direction minus the circle radius. It is therefore 0 on the circle, positive for directions outside of the cone delimited by the circle, and negative inside the cone.
    
    Parameters:
    
    direction - direction to check
    
    Returns:
    
    offset of the direction
    
    See Also:
    
    getOffset(Point)
  - sameOrientationAs
```
public boolean sameOrientationAs(Hyperplane<Sphere2D> other)
```
    Check if the instance has the same orientation as another hyperplane.
    This method is expected to be called on parallel hyperplanes. The method should not re-check for parallelism, only for orientation, typically by testing something like the sign of the dot-products of normals.
    
    Specified by:
    
    sameOrientationAs in interface Hyperplane<Sphere2D>
    
    Parameters:
    
    other - other hyperplane to check against the instance
    
    Returns:
    
    true if the instance and the other hyperplane have the same orientation
  - getArc
```
public Arc getArc(S2Point a,
                  S2Point b)
```
    Get the arc on this circle between two defining points. Only the point's projection on the circle matters, which is computed using getPhase(Vector3D).
    
    Parameters:
    
    a - first point.
    
    b - second point.
    
    Returns:
    
    an arc of the circle.
  - getTransform
```
public static Transform<Sphere2D,Sphere1D> getTransform(Rotation rotation)
```
    Get a Transform embedding a 3D rotation.
    
    Parameters:
    
    rotation - rotation to use
    
    Returns:
    
    a new transform that can be applied to either Point, Line or SubHyperplane instances

Class Circle

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Circle

Circle

Circle

Method Detail

copySelf

reset

revertSelf

getReverse

project

getTolerance

toSubSpace

getPhase

toSpace

getPointAt

getXAxis

getYAxis

getPole

getInsideArc

wholeHyperplane

emptyHyperplane

wholeSpace

getOffset

getOffset

sameOrientationAs

getArc

getTransform