com.graphhopper.util

Class DistanceCalcEarth

java.lang.Object

com.graphhopper.util.DistanceCalcEarth

All Implemented Interfaces:

DistanceCalc

Direct Known Subclasses:

DistanceCalc3D, DistancePlaneProjection

public class DistanceCalcEarth
extends Object
implements DistanceCalc

Author:

Peter Karich

Field Summary

Fields

Modifier and Type	Field and Description
static double	C Circumference of the earth
static double	KM_MILE
static double	METERS_PER_DEGREE
static double	R mean radius of the earth
static double	R_EQ Radius of the earth at equator

Constructor Summary

Constructors

Constructor and Description
DistanceCalcEarth()

Method Summary

Modifier and Type	Method and Description
double	calcCircumference(double lat) Circumference of the earth at different latitudes (breitengrad)
GHPoint	calcCrossingPointToEdge(double r_lat_deg, double r_lon_deg, double a_lat_deg, double a_lon_deg, double b_lat_deg, double b_lon_deg)
double	calcDenormalizedDist(double normedDist) Inverse to calcNormalizedDist.
double	calcDist(double fromLat, double fromLon, double toLat, double toLon) Calculates distance of (from, to) in meter.
double	calcDist3D(double fromLat, double fromLon, double fromHeight, double toLat, double toLon, double toHeight) This implements a rather quick solution to calculate 3D distances on earth using euclidean geometry mixed with Haversine formula used for the on earth distance.
double	calcNormalizedDist(double dist) Returns the specified length in normalized meter.
double	calcNormalizedDist(double fromLat, double fromLon, double toLat, double toLon) Calculates in normalized meter
double	calcNormalizedEdgeDistance(double r_lat_deg, double r_lon_deg, double a_lat_deg, double a_lon_deg, double b_lat_deg, double b_lon_deg) This method calculates the distance from r to edge (a, b) where the crossing point is c
double	calcNormalizedEdgeDistance3D(double r_lat_deg, double r_lon_deg, double r_ele_m, double a_lat_deg, double a_lon_deg, double a_ele_m, double b_lat_deg, double b_lon_deg, double b_ele_m) This method calculates the distance from r to edge (a, b) where the crossing point is c including elevation
double	calcNormalizedEdgeDistanceNew(double r_lat_deg, double r_lon_deg, double a_lat_deg, double a_lon_deg, double b_lat_deg, double b_lon_deg, boolean reduceToSegment) New edge distance calculation where no validEdgeDistance check would be necessary
BBox	createBBox(double lat, double lon, double radiusInMeter)
protected boolean	hasElevationDiff(double a, double b)
boolean	isCrossBoundary(double lon1, double lon2)
boolean	isDateLineCrossOver(double lon1, double lon2)
GHPoint	projectCoordinate(double latInDeg, double lonInDeg, double distanceInMeter, double headingClockwiseFromNorth) This methods creates a point (lat, lon in degrees) in a certain distance and direction from the specified point (lat, lon in degrees).
String	toString()
boolean	validEdgeDistance(double r_lat_deg, double r_lon_deg, double a_lat_deg, double a_lon_deg, double b_lat_deg, double b_lon_deg) This method decides for case 1: if we should use distance(r to edge) where r=(lat,lon) or case 2: min(distance(r to a), distance(r to b)) where edge=(a to b).

Methods inherited from class java.lang.Object

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

Field Detail

R

public static final double R

mean radius of the earth

See Also:

Constant Field Values

R_EQ

public static final double R_EQ

Radius of the earth at equator

See Also:

Constant Field Values

C

public static final double C

Circumference of the earth

See Also:

Constant Field Values

KM_MILE

public static final double KM_MILE

See Also:

Constant Field Values

METERS_PER_DEGREE

public static final double METERS_PER_DEGREE

See Also:

Constant Field Values

Constructor Detail

DistanceCalcEarth

public DistanceCalcEarth()

Method Detail

calcDist

public double calcDist(double fromLat,
                       double fromLon,
                       double toLat,
                       double toLon)

Calculates distance of (from, to) in meter.

http://en.wikipedia.org/wiki/Haversine_formula a = sin²(Δlat/2) + cos(lat1).cos(lat2).sin²(Δlong/2) c = 2.atan2(√a, √(1−a)) d = R.c

Specified by:

calcDist in interface DistanceCalc

calcDist3D

public double calcDist3D(double fromLat,
                         double fromLon,
                         double fromHeight,
                         double toLat,
                         double toLon,
                         double toHeight)

This implements a rather quick solution to calculate 3D distances on earth using euclidean geometry mixed with Haversine formula used for the on earth distance. The haversine formula makes not so much sense as it is only important for large distances where then the rather smallish heights would becomes negligible.

Specified by:

calcDist3D in interface DistanceCalc

calcDenormalizedDist

public double calcDenormalizedDist(double normedDist)

Description copied from interface: DistanceCalc

Inverse to calcNormalizedDist. Returned the length in meter.

Specified by:

calcDenormalizedDist in interface DistanceCalc

calcNormalizedDist

public double calcNormalizedDist(double dist)

Returns the specified length in normalized meter.

Specified by:

calcNormalizedDist in interface DistanceCalc

calcNormalizedDist

public double calcNormalizedDist(double fromLat,
                                 double fromLon,
                                 double toLat,
                                 double toLon)

Description copied from interface: DistanceCalc

Calculates in normalized meter

Specified by:

calcNormalizedDist in interface DistanceCalc

calcCircumference

public double calcCircumference(double lat)

Circumference of the earth at different latitudes (breitengrad)

Specified by:

calcCircumference in interface DistanceCalc

isDateLineCrossOver

public boolean isDateLineCrossOver(double lon1,
                                   double lon2)

createBBox

public BBox createBBox(double lat,
                       double lon,
                       double radiusInMeter)

Specified by:

createBBox in interface DistanceCalc

calcNormalizedEdgeDistance

public double calcNormalizedEdgeDistance(double r_lat_deg,
                                         double r_lon_deg,
                                         double a_lat_deg,
                                         double a_lon_deg,
                                         double b_lat_deg,
                                         double b_lon_deg)

Description copied from interface: DistanceCalc

This method calculates the distance from r to edge (a, b) where the crossing point is c

Specified by:

calcNormalizedEdgeDistance in interface DistanceCalc

Returns:

the distance in normalized meter

calcNormalizedEdgeDistance3D

public double calcNormalizedEdgeDistance3D(double r_lat_deg,
                                           double r_lon_deg,
                                           double r_ele_m,
                                           double a_lat_deg,
                                           double a_lon_deg,
                                           double a_ele_m,
                                           double b_lat_deg,
                                           double b_lon_deg,
                                           double b_ele_m)

Description copied from interface: DistanceCalc

This method calculates the distance from r to edge (a, b) where the crossing point is c including elevation

Specified by:

calcNormalizedEdgeDistance3D in interface DistanceCalc

Returns:

the distance in normalized meter

calcNormalizedEdgeDistanceNew

public double calcNormalizedEdgeDistanceNew(double r_lat_deg,
                                            double r_lon_deg,
                                            double a_lat_deg,
                                            double a_lon_deg,
                                            double b_lat_deg,
                                            double b_lon_deg,
                                            boolean reduceToSegment)

New edge distance calculation where no validEdgeDistance check would be necessary

Returns:

the normalized distance of the query point "r" to the project point "c" onto the line segment a-b

calcCrossingPointToEdge

public GHPoint calcCrossingPointToEdge(double r_lat_deg,
                                       double r_lon_deg,
                                       double a_lat_deg,
                                       double a_lon_deg,
                                       double b_lat_deg,
                                       double b_lon_deg)

Specified by:

calcCrossingPointToEdge in interface DistanceCalc

Returns:

the crossing point c of the vertical line from r to line (a, b)

validEdgeDistance

public boolean validEdgeDistance(double r_lat_deg,
                                 double r_lon_deg,
                                 double a_lat_deg,
                                 double a_lon_deg,
                                 double b_lat_deg,
                                 double b_lon_deg)

Description copied from interface: DistanceCalc

This method decides for case 1: if we should use distance(r to edge) where r=(lat,lon) or case 2: min(distance(r to a), distance(r to b)) where edge=(a to b). Note that due to rounding errors it cannot properly detect if it is case 1 or 90°.

 case 1 (including ):
   r
  .
 a-------b
 

 case 2:
 r
  .
    a-------b
 

Specified by:

validEdgeDistance in interface DistanceCalc

Returns:

true for case 1 which is "on edge" or the special case of 90° to the edge

projectCoordinate

public GHPoint projectCoordinate(double latInDeg,
                                 double lonInDeg,
                                 double distanceInMeter,
                                 double headingClockwiseFromNorth)

Description copied from interface: DistanceCalc

This methods creates a point (lat, lon in degrees) in a certain distance and direction from the specified point (lat, lon in degrees). The heading is measured clockwise from north in degrees. The distance is passed in meter.

Specified by:

projectCoordinate in interface DistanceCalc

isCrossBoundary

public boolean isCrossBoundary(double lon1,
                               double lon2)

Specified by:

isCrossBoundary in interface DistanceCalc

hasElevationDiff

protected boolean hasElevationDiff(double a,
                                   double b)

toString

public String toString()

Overrides:

toString in class Object