com.graphhopper.util

Class AngleCalc

java.lang.Object

com.graphhopper.util.AngleCalc

public class AngleCalc
extends Object

Calculates the angle of a turn, defined by three points. The fast atan2 method is from Jim Shima, 1999, http://www.dspguru.com/dsp/tricks/fixed-point-atan2-with-self-normalization and stands under public domain.

Author:

Johannes Pelzer, Peter Karich

Constructor Summary

Constructors

Constructor and Description
AngleCalc()

Method Summary

Modifier and Type	Method and Description
double	alignOrientation(double baseOrientation, double orientation) Change the representation of an orientation, so the difference to the given baseOrientation will be smaller or equal to PI (180 degree).
double	calcAzimuth(double lat1, double lon1, double lat2, double lon2) Calculate the azimuth in degree for a line given by two coordinates.
double	calcOrientation(double lat1, double lon1, double lat2, double lon2)
double	calcOrientation(double lat1, double lon1, double lat2, double lon2, boolean exact) Return orientation of line relative to east.
double	convertAzimuth2xaxisAngle(double azimuth) convert north based clockwise azimuth (0, 360) into x-axis/east based angle (-Pi, Pi)
boolean	isClockwise(double aX, double aY, double bX, double bY, double cX, double cY)

Methods inherited from class java.lang.Object

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

Constructor Detail

AngleCalc

public AngleCalc()

Method Detail

calcOrientation

public double calcOrientation(double lat1,
                              double lon1,
                              double lat2,
                              double lon2)

calcOrientation

public double calcOrientation(double lat1,
                              double lon1,
                              double lat2,
                              double lon2,
                              boolean exact)

Return orientation of line relative to east.

Parameters:

exact - If false the atan gets calculated faster, but it might contain small errors

Returns:

Orientation in interval -pi to +pi where 0 is east

convertAzimuth2xaxisAngle

public double convertAzimuth2xaxisAngle(double azimuth)

convert north based clockwise azimuth (0, 360) into x-axis/east based angle (-Pi, Pi)

alignOrientation

public double alignOrientation(double baseOrientation,
                               double orientation)

Change the representation of an orientation, so the difference to the given baseOrientation will be smaller or equal to PI (180 degree). This is achieved by adding or subtracting a 2*PI, so the direction of the orientation will not be changed

calcAzimuth

public double calcAzimuth(double lat1,
                          double lon1,
                          double lat2,
                          double lon2)

Calculate the azimuth in degree for a line given by two coordinates. Direction in 'degree' where 0 is north, 90 is east, 180 is south and 270 is west.

isClockwise

public boolean isClockwise(double aX,
                           double aY,
                           double bX,
                           double bY,
                           double cX,
                           double cY)

Returns:

true if the given vectors follow a clockwise order abc, bca or cab, false if the order is counter-clockwise cba, acb or bac, e.g. this returns true: a b | / 0 - c