Class Angle

java.lang.Object
org.locationtech.jts.algorithm.Angle

public class Angle extends Object
Utility functions for working with angles. Unless otherwise noted, methods in this class express angles in radians.
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    Constant representing clockwise orientation
    static final int
    Constant representing counterclockwise orientation
    static final int
    Constant representing no orientation
    static final double
    The value of Pi/2
    static final double
    The value of Pi/4
    static final double
    The value of 2*Pi
  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    Returns the angle of the vector from (0,0) to p, relative to the positive X-axis.
    static double
    Returns the angle of the vector from p0 to p1, relative to the positive X-axis.
    static double
    Returns the unoriented smallest angle between two vectors.
    static double
    Returns the oriented smallest angle between two vectors.
    static double
    Computes the angle of the unoriented bisector of the smallest angle between two vectors.
    static double
    diff(double ang1, double ang2)
    Computes the unoriented smallest difference between two angles.
    static int
    getTurn(double ang1, double ang2)
    Returns whether an angle must turn clockwise or counterclockwise to overlap another angle.
    static double
    Computes the interior angle between two segments of a ring.
    static boolean
    Tests whether the angle between p0-p1-p2 is acute.
    static boolean
    Tests whether the angle between p0-p1-p2 is obtuse.
    static double
    normalize(double angle)
    Computes the normalized value of an angle, which is the equivalent angle in the range ( -Pi, Pi ].
    static double
    normalizePositive(double angle)
    Computes the normalized positive value of an angle, which is the equivalent angle in the range [ 0, 2*Pi ).
    static Coordinate
    project(Coordinate p, double angle, double dist)
    Projects a point by a given angle and distance.
    static double
    toDegrees(double radians)
    Converts from radians to degrees.
    static double
    toRadians(double angleDegrees)
    Converts from degrees to radians.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • PI_TIMES_2

      public static final double PI_TIMES_2
      The value of 2*Pi
      See Also:
    • PI_OVER_2

      public static final double PI_OVER_2
      The value of Pi/2
      See Also:
    • PI_OVER_4

      public static final double PI_OVER_4
      The value of Pi/4
      See Also:
    • COUNTERCLOCKWISE

      public static final int COUNTERCLOCKWISE
      Constant representing counterclockwise orientation
      See Also:
    • CLOCKWISE

      public static final int CLOCKWISE
      Constant representing clockwise orientation
      See Also:
    • NONE

      public static final int NONE
      Constant representing no orientation
      See Also:
  • Method Details

    • toDegrees

      public static double toDegrees(double radians)
      Converts from radians to degrees.
      Parameters:
      radians - an angle in radians
      Returns:
      the angle in degrees
    • toRadians

      public static double toRadians(double angleDegrees)
      Converts from degrees to radians.
      Parameters:
      angleDegrees - an angle in degrees
      Returns:
      the angle in radians
    • angle

      public static double angle(Coordinate p0, Coordinate p1)
      Returns the angle of the vector from p0 to p1, relative to the positive X-axis. The angle is normalized to be in the range [ -Pi, Pi ].
      Parameters:
      p0 - the initial point of the vector
      p1 - the terminal point of the vector
      Returns:
      the normalized angle (in radians) that p0-p1 makes with the positive x-axis.
    • angle

      public static double angle(Coordinate p)
      Returns the angle of the vector from (0,0) to p, relative to the positive X-axis. The angle is normalized to be in the range ( -Pi, Pi ].
      Parameters:
      p - the terminal point of the vector
      Returns:
      the normalized angle (in radians) that p makes with the positive x-axis.
    • isAcute

      public static boolean isAcute(Coordinate p0, Coordinate p1, Coordinate p2)
      Tests whether the angle between p0-p1-p2 is acute. An angle is acute if it is less than 90 degrees.

      Note: this implementation is not precise (deterministic) for angles very close to 90 degrees.

      Parameters:
      p0 - an endpoint of the angle
      p1 - the base of the angle
      p2 - the other endpoint of the angle
      Returns:
      true if the angle is acute
    • isObtuse

      public static boolean isObtuse(Coordinate p0, Coordinate p1, Coordinate p2)
      Tests whether the angle between p0-p1-p2 is obtuse. An angle is obtuse if it is greater than 90 degrees.

      Note: this implementation is not precise (deterministic) for angles very close to 90 degrees.

      Parameters:
      p0 - an endpoint of the angle
      p1 - the base of the angle
      p2 - the other endpoint of the angle
      Returns:
      true if the angle is obtuse
    • angleBetween

      public static double angleBetween(Coordinate tip1, Coordinate tail, Coordinate tip2)
      Returns the unoriented smallest angle between two vectors. The computed angle will be in the range [0, Pi).
      Parameters:
      tip1 - the tip of one vector
      tail - the tail of each vector
      tip2 - the tip of the other vector
      Returns:
      the angle between tail-tip1 and tail-tip2
    • angleBetweenOriented

      public static double angleBetweenOriented(Coordinate tip1, Coordinate tail, Coordinate tip2)
      Returns the oriented smallest angle between two vectors. The computed angle will be in the range (-Pi, Pi]. A positive result corresponds to a counterclockwise (CCW) rotation from v1 to v2; a negative result corresponds to a clockwise (CW) rotation; a zero result corresponds to no rotation.
      Parameters:
      tip1 - the tip of v1
      tail - the tail of each vector
      tip2 - the tip of v2
      Returns:
      the angle between v1 and v2, relative to v1
    • bisector

      public static double bisector(Coordinate tip1, Coordinate tail, Coordinate tip2)
      Computes the angle of the unoriented bisector of the smallest angle between two vectors. The computed angle will be in the range (-Pi, Pi].
      Parameters:
      tip1 - the tip of v1
      tail - the tail of each vector
      tip2 - the tip of v2
      Returns:
      the angle of the bisector between v1 and v2
    • interiorAngle

      public static double interiorAngle(Coordinate p0, Coordinate p1, Coordinate p2)
      Computes the interior angle between two segments of a ring. The ring is assumed to be oriented in a clockwise direction. The computed angle will be in the range [0, 2Pi]
      Parameters:
      p0 - a point of the ring
      p1 - the next point of the ring
      p2 - the next point of the ring
      Returns:
      the interior angle based at p1
    • getTurn

      public static int getTurn(double ang1, double ang2)
      Returns whether an angle must turn clockwise or counterclockwise to overlap another angle.
      Parameters:
      ang1 - an angle (in radians)
      ang2 - an angle (in radians)
      Returns:
      whether a1 must turn CLOCKWISE, COUNTERCLOCKWISE or NONE to overlap a2.
    • normalize

      public static double normalize(double angle)
      Computes the normalized value of an angle, which is the equivalent angle in the range ( -Pi, Pi ].
      Parameters:
      angle - the angle to normalize
      Returns:
      an equivalent angle in the range (-Pi, Pi]
    • normalizePositive

      public static double normalizePositive(double angle)
      Computes the normalized positive value of an angle, which is the equivalent angle in the range [ 0, 2*Pi ). E.g.:
      • normalizePositive(0.0) = 0.0
      • normalizePositive(-PI) = PI
      • normalizePositive(-2PI) = 0.0
      • normalizePositive(-3PI) = PI
      • normalizePositive(-4PI) = 0
      • normalizePositive(PI) = PI
      • normalizePositive(2PI) = 0.0
      • normalizePositive(3PI) = PI
      • normalizePositive(4PI) = 0.0
      Parameters:
      angle - the angle to normalize, in radians
      Returns:
      an equivalent positive angle
    • diff

      public static double diff(double ang1, double ang2)
      Computes the unoriented smallest difference between two angles. The angles are assumed to be normalized to the range [-Pi, Pi]. The result will be in the range [0, Pi].
      Parameters:
      ang1 - the angle of one vector (in [-Pi, Pi] )
      ang2 - the angle of the other vector (in range [-Pi, Pi] )
      Returns:
      the angle (in radians) between the two vectors (in range [0, Pi] )
    • project

      public static Coordinate project(Coordinate p, double angle, double dist)
      Projects a point by a given angle and distance.
      Parameters:
      p - the point to project
      angle - the angle at which to project
      dist - the distance to project
      Returns:
      the projected point