org.geolatte.geom

Class Vector

java.lang.Object

org.geolatte.geom.Vector

public class Vector
extends Object

A set of utility functions for basic 2D vector functions.

Author:

Karel Maesen, Geovise BVBA creation-date: 4/7/12

Constructor Summary

Constructors

Constructor and Description
Vector()

Method Summary

Modifier and Type	Method and Description
static Point	add(Point p0, Point p1) Adds two Points.
static double	dot(Point p0, Point p1) Returns the dot-product of the specified Points
static double	dot(Point p0, Point p1, boolean limit2D) Returns the dot-product of the specified Points
static Point	perp(Point p) Hill's "perp" operator.
static double	perpDot(Point p0, Point p1) Applies the perp dot-operation on the specified Points
static double[]	pointToSegment2D(Point p0, Point p1, Point y) Returns the squared distance and projectionfactor of the point y on the linesegment defined by points p0 and p1
static Point	substract(Point p0, Point p1) Subtracts two Points.

Methods inherited from class java.lang.Object

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

Constructor Detail

Vector

public Vector()

Method Detail

pointToSegment2D

public static double[] pointToSegment2D(Point p0,
                                        Point p1,
                                        Point y)

Returns the squared distance and projectionfactor of the point y on the linesegment defined by points p0 and p1

The projection factor is the value for t that determines the projection of y on the line p0 + t*(p1-p0).

Parameters:

p0 - the start point of the line segment

p1 - the end point of the line segment

y - the point to project onto the linesegment

Returns:

an array of length 2, with first element being the squared distance of Point y to the linesegment, and second element the projection factor

dot

public static double dot(Point p0,
                         Point p1)

Returns the dot-product of the specified Points

Parameters:

p0 - first operand

p1 - second operand

Returns:

the dot-product of p0 and p1

dot

public static double dot(Point p0,
                         Point p1,
                         boolean limit2D)

Returns the dot-product of the specified Points

If limit2D is set to true, Z-coordinates will be ignored so that the product is calculated in 2D.

If any of the parameters are 2D, the operation is performed in 2D.

Parameters:

p0 - first operand

p1 - second operand

limit2D - if true, the dot-product will be in 2D.

Returns:

the dot-product of p0 and p1.

add

public static Point add(Point p0,
                        Point p1)

Adds two Points.

If any of the parameters are 2D, the operation is performed in 2D.

Parameters:

p0 - first operand

p1 - second operand

substract

public static Point substract(Point p0,
                              Point p1)

Subtracts two Points.

If any of the parameters are 2D, the operation is performed in 2D.

Parameters:

p0 - first operand

p1 - second operand

perp

public static Point perp(Point p)

Hill's "perp" operator.

The application of this operator on a vector P returns the vector perpendicular at 90 deg. counterclockwise from P in the 2D (X/Y) plane.

Parameters:

p - a vector represented by a point.

Returns:

the vector perpendicular to p in the 2D-plane, at 90 deg. counterclockwise.

perpDot

public static double perpDot(Point p0,
                             Point p1)

Applies the perp dot-operation on the specified Points

The perp dot operation on vectors P, Q is defined as dot(perp(P),Q).

This operation will be performed in 2D only.

Parameters:

p0 - first operand

p1 - second operand

Returns:

the Perp dot of p0 and p1.