geos::algorithm::Angle Class Reference

Utility functions for working with angles. More...

#include <Angle.h>

List of all members.

Static Public Member Functions
static double	toDegrees (double radians)
	Converts from radians to degrees.
static double	toRadians (double angleDegrees)
	Converts from degrees to radians.
static double	angle (const geom::Coordinate &p0, const geom::Coordinate &p1)
	Returns the angle of the vector from p0 to p1, relative to the positive X-axis.
static double	angle (const geom::Coordinate &p)
	Returns the angle that the vector from (0,0) to p, relative to the positive X-axis.
static bool	isAcute (const geom::Coordinate &p0, const geom::Coordinate &p1, const geom::Coordinate &p2)
	Tests whether the angle between p0-p1-p2 is acute.
static bool	isObtuse (const geom::Coordinate &p0, const geom::Coordinate &p1, const geom::Coordinate &p2)
	Tests whether the angle between p0-p1-p2 is obtuse.
static double	angleBetween (const geom::Coordinate &tip1, const geom::Coordinate &tail, const geom::Coordinate &tip2)
	Returns the unoriented smallest angle between two vectors.
static double	angleBetweenOriented (const geom::Coordinate &tip1, const geom::Coordinate &tail, const geom::Coordinate &tip2)
	Returns the oriented smallest angle between two vectors.
static double	interiorAngle (const geom::Coordinate &p0, const geom::Coordinate &p1, const geom::Coordinate &p2)
	Computes the interior angle between two segments of a ring.
static int	getTurn (double ang1, double ang2)
	Returns whether an angle must turn clockwise or counterclockwise to overlap another angle.
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 double	diff (double ang1, double ang2)
	Computes the unoriented smallest difference between two angles.
Static Public Attributes
static const double	PI_TIMES_2
static const double	PI_OVER_2
static const double	PI_OVER_4
static const int	COUNTERCLOCKWISE = CGAlgorithms::COUNTERCLOCKWISE
	Constant representing counterclockwise orientation.
static const int	CLOCKWISE = CGAlgorithms::CLOCKWISE
	Constant representing clockwise orientation.
static const int	NONE = CGAlgorithms::COLLINEAR
	Constant representing no orientation.

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Detailed Description

Utility functions for working with angles.

Unless otherwise noted, methods in this class express angles in radians.

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Member Function Documentation

static double geos::algorithm::Angle::angle (  const geom::Coordinate &  p  )  [static]

Returns the angle that the vector from (0,0) to p, relative to the positive X-axis. The angle is normalized to be in the range ( -Pi, Pi ]. Returns: the normalized angle (in radians) that p makes with the positive x-axis.

static double geos::algorithm::Angle::angle (  const geom::Coordinate &  p0, const geom::Coordinate &  p1 )  [static]

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 ]. Returns: the normalized angle (in radians) that p0-p1 makes with the positive x-axis.

static double geos::algorithm::Angle::angleBetween (  const geom::Coordinate &  tip1, const geom::Coordinate &  tail, const geom::Coordinate &  tip2 )  [static]

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

static double geos::algorithm::Angle::angleBetweenOriented (  const geom::Coordinate &  tip1, const geom::Coordinate &  tail, const geom::Coordinate &  tip2 )  [static]

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 rotation from v1 to v2; a negative result corresponds to a clockwise 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

static double geos::algorithm::Angle::diff (  double  ang1, double  ang2 )  [static]

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] )

static int geos::algorithm::Angle::getTurn (  double  ang1, double  ang2 )  [static]

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.

static double geos::algorithm::Angle::interiorAngle (  const geom::Coordinate &  p0, const geom::Coordinate &  p1, const geom::Coordinate &  p2 )  [static]

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

static bool geos::algorithm::Angle::isAcute (  const geom::Coordinate &  p0, const geom::Coordinate &  p1, const geom::Coordinate &  p2 )  [static]

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 (determistic) 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

static bool geos::algorithm::Angle::isObtuse (  const geom::Coordinate &  p0, const geom::Coordinate &  p1, const geom::Coordinate &  p2 )  [static]

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 (determistic) 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

static double geos::algorithm::Angle::normalize (  double  angle  )  [static]

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]

static double geos::algorithm::Angle::normalizePositive (  double  angle  )  [static]

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

static double geos::algorithm::Angle::toDegrees (  double  radians  )  [static]

Converts from radians to degrees. Parameters: radians  an angle in radians Returns: the angle in degrees

static double geos::algorithm::Angle::toRadians (  double  angleDegrees  )  [static]

Converts from degrees to radians. Parameters: angleDegrees  an angle in degrees Returns: the angle in radians

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The documentation for this class was generated from the following file:

• Angle.h

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