PamUtils

Class BearingMean

java.lang.Object

PamUtils.BearingMean

public class BearingMean
extends java.lang.Object

Calculate the mean of a load of angles in degrees.

This is tricky, since the mean of 359 and 1 is 0, so the first thing to do is to try to find the centre of where most angles are, then we calculate all angles relative to that reference point, and finally, get the mean.

Strategy is to calculate a unit vector for each bearing, then take the mean vector. If all bearings cancel each other out, then the bearing returned will be NaN.

function has been put into a class like this so that it can go further and calculate the standard deviation as well should it feel like it.

Author:

Doug Gillespie.

Constructor Summary

Constructors

Constructor and Description
BearingMean(double[] bearings)

Method Summary

Methods

Modifier and Type	Method and Description
double	getBearingMean()
double	getBearingR() Magnitude of resultant vector r.
double	getBearingSTD() Get the standard deviation about the mean.
double	getBearingSTD2() The standard deviation of as defined by Zar (1999) sqrt(2*(1-R))

Methods inherited from class java.lang.Object

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

Constructor Detail

BearingMean

public BearingMean(double[] bearings)

Method Detail

getBearingMean

public double getBearingMean()

Returns:

the bearingMean

getBearingSTD

public double getBearingSTD()

Get the standard deviation about the mean.

Returns:

the standard deviation about the mean.

getBearingR

public double getBearingR()

Magnitude of resultant vector r. This quantity is used for calculating circular variance, circular standard deviation

Returns:

R - the magnitude of the resultant vector

getBearingSTD2

public double getBearingSTD2()

The standard deviation of as defined by Zar (1999) sqrt(2*(1-R))

Returns:

Circular standard deviation