Package org.meteoinfo.jts.algorithm

Class NonRobustCGAlgorithms

java.lang.Object

org.meteoinfo.jts.algorithm.CGAlgorithms

org.meteoinfo.jts.algorithm.NonRobustCGAlgorithms

public class NonRobustCGAlgorithms
extends CGAlgorithms

Non-robust versions of various fundamental Computational Geometric algorithms, FOR TESTING PURPOSES ONLY!. The non-robustness is due to rounding error in floating point computation.

Field Summary

Fields inherited from class org.meteoinfo.jts.algorithm.CGAlgorithms

CLOCKWISE, COLLINEAR, COUNTERCLOCKWISE, LEFT, RIGHT, STRAIGHT

Constructor Summary

Constructors

Constructor	Description
NonRobustCGAlgorithms()

Method Summary

Modifier and Type	Method	Description
static int	computeOrientation(Coordinate p1, Coordinate p2, Coordinate q)	Computes the orientation of a point q to the directed line segment p1-p2.
static double	distanceLineLine(Coordinate A, Coordinate B, Coordinate C, Coordinate D)	Computes the distance from a line segment AB to a line segment CD Note: NON-ROBUST!
static boolean	isCCW(Coordinate[] ring)	Computes whether a ring defined by an array of Coordinate is oriented counter-clockwise.
static boolean	isPointInRing(Coordinate p, Coordinate[] ring)	Computes whether a ring defined by an array of Coordinate is oriented counter-clockwise.
static int	orientationIndex(Coordinate p1, Coordinate p2, Coordinate q)	Returns the index of the direction of the point q relative to a vector specified by p1-p2.

Methods inherited from class org.meteoinfo.jts.algorithm.CGAlgorithms

distancePointLine, distancePointLine, distancePointLinePerpendicular, isOnLine, length, locatePointInRing, signedArea, signedArea

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NonRobustCGAlgorithms

public NonRobustCGAlgorithms()

Method Detail

isPointInRing

public static boolean isPointInRing(Coordinate p,
                                    Coordinate[] ring)

Computes whether a ring defined by an array of Coordinate is oriented counter-clockwise.

This will handle coordinate lists which contain repeated points.

Parameters:

ring - an array of coordinates forming a ring

Returns:

true if the ring is oriented counter-clockwise.

Throws:

java.lang.IllegalArgumentException - if the ring is degenerate (does not contain 3 different points)

isCCW

public static boolean isCCW(Coordinate[] ring)

Computes whether a ring defined by an array of Coordinate is oriented counter-clockwise.

This will handle coordinate lists which contain repeated points.

Parameters:

ring - an array of coordinates forming a ring

Returns:

true if the ring is oriented counter-clockwise.

Throws:

java.lang.IllegalArgumentException - if the ring is degenerate (does not contain 3 different points)

computeOrientation

public static int computeOrientation(Coordinate p1,
                                     Coordinate p2,
                                     Coordinate q)

Computes the orientation of a point q to the directed line segment p1-p2. The orientation of a point relative to a directed line segment indicates which way you turn to get to q after travelling from p1 to p2.

Returns:

1 if q is counter-clockwise from p1-p2

orientationIndex

public static int orientationIndex(Coordinate p1,
                                   Coordinate p2,
                                   Coordinate q)

Returns the index of the direction of the point q relative to a vector specified by p1-p2.

Parameters:

p1 - the origin point of the vector

p2 - the final point of the vector

q - the point to compute the direction to

Returns:

1 if q is counter-clockwise (left) from p1-p2

distanceLineLine

public static double distanceLineLine(Coordinate A,
                                      Coordinate B,
                                      Coordinate C,
                                      Coordinate D)

Computes the distance from a line segment AB to a line segment CD Note: NON-ROBUST!

Parameters:

A - a point of one line

B - the second point of (must be different to A)

C - one point of the line

D - another point of the line (must be different to A)