org.geolatte.geom.cga

Class NumericalMethods

java.lang.Object

org.geolatte.geom.cga.NumericalMethods

public class NumericalMethods
extends java.lang.Object

Created by Karel Maesen, Geovise BVBA on 01/03/15.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NumericalMethods.TwoSum

Constructor Summary

Constructors

Constructor and Description
NumericalMethods()

Method Summary

Modifier and Type	Method and Description
static boolean	collinear(Position p0, Position p1, Position p2)
static double	crossProduct(double x0, double y0, double x1, double y1)
private static double	deltaDeterminant(Position p0, Position p1, Position p2)
static double	determinant(double a11, double a12, double a21, double a22) Calculates the determinant of a 2x2 matrix
static double	determinant(double a11, double a12, double a13, double a21, double a22, double a23, double a31, double a32, double a33) Calculates the determinant of a 3x3 matrix
static boolean	isCounterClockwise(LinearRing<?> ring) Determines whether the specified LinearRing is counter-clockwise.
static boolean	isCounterClockwise(Position p0, Position p1, Position p2) Determines if the triangle determined by p0, p1, p2 is counterclockwise in 2D.
static boolean	isCounterClockwise(PositionSequence<?> positions) Determines whether the specified PositionSequence is counter-clockwise.
private static double	shoelaceStep(java.lang.Integer idx, LinearRing<?> ring)

Methods inherited from class java.lang.Object

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

Constructor Detail

NumericalMethods

public NumericalMethods()

Method Detail

determinant

public static double determinant(double a11,
                                 double a12,
                                 double a21,
                                 double a22)

Calculates the determinant of a 2x2 matrix

Parameters:

a11 -

a12 -

a21 -

a22 -

Returns:

the determinant

crossProduct

public static double crossProduct(double x0,
                                  double y0,
                                  double x1,
                                  double y1)

determinant

public static double determinant(double a11,
                                 double a12,
                                 double a13,
                                 double a21,
                                 double a22,
                                 double a23,
                                 double a31,
                                 double a32,
                                 double a33)

Calculates the determinant of a 3x3 matrix

Parameters:

a11 -

a12 -

a13 -

a21 -

a22 -

a23 -

a31 -

a32 -

a33 -

Returns:

isCounterClockwise

public static boolean isCounterClockwise(Position p0,
                                         Position p1,
                                         Position p2)

Determines if the triangle determined by p0, p1, p2 is counterclockwise in 2D.

This is equivalent to p2 is to the left of the line p0 - p1.

Parameters:

p0 -

p1 -

p2 -

Returns:

true if counterclockwise

isCounterClockwise

public static boolean isCounterClockwise(PositionSequence<?> positions)

Determines whether the specified PositionSequence is counter-clockwise.

Only the first three positions, are inspected to determine whether the sequence is counter-clockwise. In case are less than three positions in the sequence, the method returns true.

Parameters:

positions - a PositionSequence

Returns:

true if the positions in the specified sequence are counter-clockwise, or if the sequence contains less than three elements.

isCounterClockwise

public static boolean isCounterClockwise(LinearRing<?> ring)

Determines whether the specified LinearRing is counter-clockwise.

Orientation is determined by calculating the signed area of the given ring and using the sign to determine the orientation

The specified Ring is assumed to be valid.

Parameters:

ring - a LinearRing

Returns:

true if the positions of the ring describe it counter-clockwise

shoelaceStep

private static double shoelaceStep(java.lang.Integer idx,
                                   LinearRing<?> ring)

collinear

public static boolean collinear(Position p0,
                                Position p1,
                                Position p2)

deltaDeterminant

private static double deltaDeterminant(Position p0,
                                       Position p1,
                                       Position p2)