com.luciad.geodesy

LuciadLightspeedClass TLcdSphereRhumblineUtil

java.lang.Object

com.luciad.geodesy.TLcdSphereRhumblineUtil

public class TLcdSphereRhumblineUtil
extends Object

Utility for a series of specific topology calculations with rhumblines on the sphere.

Since:

8.3.02

Method Summary

Modifier and Type	Method and Description
static double	closestPointOnRhumbline(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, double aRadius, double aRelativeTolerance, double aAbsoluteTolerance, ILcd2DEditablePoint aResultSFCT) Finds the shortest rhumb distance from point aP3 to the rhumbline segment aP1-aP2 to within an accuracy of max( aAbsoluteTolerance, aRelativeTolerance * rhumblineDistance(aP1,aP2) ).
static double	closestPointOnRhumblineGeodesic(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, double aRadius, double aRelativeTolerance, double aAbsoluteTolerance, ILcd2DEditablePoint aResultSFCT) Finds the shortest geodesic distance from point aP3 to the rhumbline segment aP1-aP2 to within an accuracy of max( aAbsoluteTolerance, aRelativeTolerance * rhumblineDistance(aP1,aP2) ).
static double	closestPointOnShape(ILcdPoint aPoint, ILcdShape aShape, ILcd2DEditablePoint aResultSFCT) Finds the shortest rhumb distance from the given point to the given shape.
static boolean	contains2D(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aPoint) Checks if the point aPoint lies on the rhumb line between aP1 and aP2.
static boolean	contains2DLS(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, ILcdPoint aP4) Checks if the rhumb line between aP1 and aP2 contains the rhumb line between aP3 and aP4.
static int	intersection2DLineSegments(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, ILcdPoint aP4, ILcd2DEditablePoint aResult1SFCT, ILcd2DEditablePoint aResult2SFCT) Computes the intersection of two rhumb lines.
static int	intersectionGeodesicRhumblineSFCT(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, ILcdPoint aP4, ILcd2DEditablePoint[] aPointsSFCT) Computes the intersection points of a geodesic and a rhumb line.
static boolean	intersects2DLS(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, ILcdPoint aP4) Checks if two rhumb lines intersect.
static boolean	intersectsGeodesicRhumbline(ILcdPoint aP1, ILcdPoint aP2, ILcdPoint aP3, ILcdPoint aP4) Checks if a geodesic and a rhumb line intersect.
static boolean	polygonContains2D(ILcdPolygon aPolygon, double aLonP, double aLatP) Checks if a point lies inside a polygon.
static double	rhumblineAzimuth2D(ILcdPoint aP1, ILcdPoint aP2) Returns the azimuth of the rhumbline path from aP1 to aP2 in DEGREES.
static double	rhumblineDistance(ILcdPoint aP1, ILcdPoint aP2, double aRadius) Returns the distance of the rhumbline path from aP1 to aP2 in meters.
static double	rhumblineDistance3D(ILcdPoint aPoint1, ILcdPoint aPoint2, double aRadius) Calculates the rhumbline distance to go from point p1 to point p2.
static void	rhumblinePointSFCT(ILcdPoint aPoint, double aDistance, double aAzimuth, double aRadius, ILcd2DEditablePoint aRhumblinePointSFCT) Determines the ILcdPoint aRhumblinePointSFCT on the rhumbline through (aP1.getX(), aP1.getY()) located at a distance aDistance and forward azimuth aAzimuth.
static void	rhumblinePointSFCT(ILcdPoint aP1, ILcdPoint aP2, double aK, ILcd2DEditablePoint aRhumblinePoint) Calculates the rhumbline point at a fraction aK of the rhumbline distance between two points aP1 and aP2.

Methods inherited from class java.lang.Object

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

Method Detail

contains2D

public static boolean contains2D(ILcdPoint aP1,
                                 ILcdPoint aP2,
                                 ILcdPoint aPoint)

Checks if the point aPoint lies on the rhumb line between aP1 and aP2.

Parameters:

aP1 - start point of the rhumb line.

aP2 - end point of the rhumb line.

aPoint - point to be checked.

Returns:

true if the point is on the rhumb line, false otherwise.

contains2DLS

public static boolean contains2DLS(ILcdPoint aP1,
                                   ILcdPoint aP2,
                                   ILcdPoint aP3,
                                   ILcdPoint aP4)

Checks if the rhumb line between aP1 and aP2 contains the rhumb line between aP3 and aP4.

Parameters:

aP1 - start point of the first rhumb line.

aP2 - end point of the first rhumb line.

aP3 - start point of the second rhumb line.

aP4 - end point of the second rhumb line.

Returns:

true if the first rhumb line contains the second, false otherwise.

polygonContains2D

public static boolean polygonContains2D(ILcdPolygon aPolygon,
                                        double aLonP,
                                        double aLatP)

Checks if a point lies inside a polygon. We define the point with coordinates aLonP,aLatP to be inside if:

• the point interacts with the polygon bounds
• the point has an odd number of polygon edge intersections within a distance of 180 degrees in northern direction (azimuth zero degrees) if this fails we also try in southern direction

The polygon thus shouldn't be larger than a hemisphere.

Parameters:

aPolygon - polygon w.r.t. which the test is performed.

aLonP - longitude of the point to be tested in degrees.

aLatP - latitude of the point to be tested in degrees.

Returns:

true if the point lies inside the polygon, false otherwise.

intersects2DLS

public static boolean intersects2DLS(ILcdPoint aP1,
                                     ILcdPoint aP2,
                                     ILcdPoint aP3,
                                     ILcdPoint aP4)

Checks if two rhumb lines intersect.

Parameters:

aP1 - start point of the first rhumb line.

aP2 - end point of the first rhumb line.

aP3 - start point of the second rhumb line.

aP4 - end point of the second rhumb line.

Returns:

true if the two rhumb lines intersect, false otherwise.

intersection2DLineSegments

public static int intersection2DLineSegments(ILcdPoint aP1,
                                             ILcdPoint aP2,
                                             ILcdPoint aP3,
                                             ILcdPoint aP4,
                                             ILcd2DEditablePoint aResult1SFCT,
                                             ILcd2DEditablePoint aResult2SFCT)

Computes the intersection of two rhumb lines.

The method has two ILcd2DEditablePoint objects as side effect parameters containing the result. They are filled in depending on the return value of the method.

Parameters:

aP1 - the start point of the first rhumb line.

aP2 - the end point of the first rhumb line.

aP3 - the start point of the second rhumb line.

aP4 - the end point of the second rhumb line.

aResult1SFCT - the intersection point (or an end point of the interval of overlapping points).

aResult2SFCT - if there is an interval of overlapping points, this contains one of the end points.

Returns:

• 0: no intersection between the two rhumb lines
• 1: the rhumb lines have one intersection point
• -1: the two rhumb lines share an interval of points

intersectsGeodesicRhumbline

public static boolean intersectsGeodesicRhumbline(ILcdPoint aP1,
                                                  ILcdPoint aP2,
                                                  ILcdPoint aP3,
                                                  ILcdPoint aP4)

Checks if a geodesic and a rhumb line intersect.

Parameters:

aP1 - start point of the geodesic.

aP2 - end point of the geodesic.

aP3 - start point of the rhumb line.

aP4 - end point of the rhumb line.

Returns:

true if the geodesic and rhumbline intersect, false otherwise.

intersectionGeodesicRhumblineSFCT

public static int intersectionGeodesicRhumblineSFCT(ILcdPoint aP1,
                                                    ILcdPoint aP2,
                                                    ILcdPoint aP3,
                                                    ILcdPoint aP4,
                                                    ILcd2DEditablePoint[] aPointsSFCT)

Computes the intersection points of a geodesic and a rhumb line. The result is filled in the given point array. The number of intersection points is returned as an integer.

Parameters:

aP1 - the start point of the geodesic.

aP2 - the end point of the geodesic.

aP3 - the start point of the rhumb line.

aP4 - the end point of the rhumb line.

aPointsSFCT - The array of points in which the results should be stored.

Returns:

The number of intersection points (> 0). If no intersection is found, 0 is returned. If the geodesic and rhumb line share an interval of points, -1 is returned. In this case, aPointsSFCT contains the two end points of this interval.

Throws:

IndexOutOfBoundsException - If the length of aPointsSFCT is smaller than the number of intersection points.

rhumblineAzimuth2D

public static double rhumblineAzimuth2D(ILcdPoint aP1,
                                        ILcdPoint aP2)

Returns the azimuth of the rhumbline path from aP1 to aP2 in DEGREES.

Parameters:

aP1 - a first point defining the rhumbline path

aP2 - a second point defining the rhumbline path

Returns:

the azimuth of the rhumbline path from aP1 to aP2 in DEGREES.

rhumblineDistance

public static double rhumblineDistance(ILcdPoint aP1,
                                       ILcdPoint aP2,
                                       double aRadius)

Returns the distance of the rhumbline path from aP1 to aP2 in meters.

Parameters:

aP1 - a first point defining the rhumbline path

aP2 - a second point defining the rhumbline path

aRadius - the radius of the sphere.

Returns:

the distance of the rhumbline path from aP1 to aP2 in meters

rhumblinePointSFCT

public static void rhumblinePointSFCT(ILcdPoint aPoint,
                                      double aDistance,
                                      double aAzimuth,
                                      double aRadius,
                                      ILcd2DEditablePoint aRhumblinePointSFCT)

Determines the ILcdPoint aRhumblinePointSFCT on the rhumbline through (aP1.getX(), aP1.getY()) located at a distance aDistance and forward azimuth aAzimuth.

Parameters:

aPoint - ILcdPoint on the sphere.

aDistance - the distance expressed in meters

aAzimuth - the forward azimuth expressed in degrees

aRadius - the radius of the sphere.

aRhumblinePointSFCT - the point in which the calculated point will be stored.

See Also:

rhumblineDistance(com.luciad.shape.ILcdPoint, com.luciad.shape.ILcdPoint, double)

rhumblinePointSFCT

public static void rhumblinePointSFCT(ILcdPoint aP1,
                                      ILcdPoint aP2,
                                      double aK,
                                      ILcd2DEditablePoint aRhumblinePoint)

Calculates the rhumbline point at a fraction aK of the rhumbline distance between two points aP1 and aP2.

Parameters:

aP1 - the first point of the rhumb line

aP2 - the second point of the rhumb line

aK - the fraction of the rhumbline distance between aP1 and aP2

aRhumblinePoint - the resulting point

closestPointOnShape

public static double closestPointOnShape(ILcdPoint aPoint,
                                         ILcdShape aShape,
                                         ILcd2DEditablePoint aResultSFCT)

Finds the shortest rhumb distance from the given point to the given shape. The corresponding point on the shape is returned in the side effect parameter.

This methods supports rhumb ILcdPolyline and ILcdPolygon instances.

For the shortest great circle distance to a rhumb shape, see TLcdSphereUtil.closestPointOnShape(com.luciad.shape.ILcdPoint, com.luciad.shape.ILcdShape, com.luciad.shape.shape2D.ILcd2DEditablePoint)

Parameters:

aPoint - the starting point

aShape - the shape for which to find the point closest to aPoint

aResultSFCT - side-effect parameter for the resulting point

Returns:

the shortest distance (meters)

Throws:

IllegalArgumentException - if the provided shape is not supported

closestPointOnRhumbline

public static double closestPointOnRhumbline(ILcdPoint aP1,
                                             ILcdPoint aP2,
                                             ILcdPoint aP3,
                                             double aRadius,
                                             double aRelativeTolerance,
                                             double aAbsoluteTolerance,
                                             ILcd2DEditablePoint aResultSFCT)

Finds the shortest rhumb distance from point aP3 to the rhumbline segment aP1-aP2 to within an accuracy of max( aAbsoluteTolerance, aRelativeTolerance * rhumblineDistance(aP1,aP2) ). The corresponding point on the rhumbline segment is returned in the side effect parameter aResultSFCT.

Parameters:

aP1 - start point of the rhumbline segment.

aP2 - end point of the rhumbline segment.

aP3 - point from which the shortest distance to the line segment is sought.

aRadius - the radius of the sphere on which to perform the calculation.

aRelativeTolerance - relative tolerance.

aAbsoluteTolerance - absolute tolerance.

aResultSFCT - contains the point on the rhumbline segment that is the shortest from point aP3.

Returns:

the rhumbline distance from point aP3 to the rhumbline segment aP1-aP2 (meters).

closestPointOnRhumblineGeodesic

public static double closestPointOnRhumblineGeodesic(ILcdPoint aP1,
                                                     ILcdPoint aP2,
                                                     ILcdPoint aP3,
                                                     double aRadius,
                                                     double aRelativeTolerance,
                                                     double aAbsoluteTolerance,
                                                     ILcd2DEditablePoint aResultSFCT)

Finds the shortest geodesic distance from point aP3 to the rhumbline segment aP1-aP2 to within an accuracy of max( aAbsoluteTolerance, aRelativeTolerance * rhumblineDistance(aP1,aP2) ). The corresponding point on the rhumbline segment is returned in the side effect parameter aResultSFCT.

Parameters:

aP1 - start point of the rhumbline segment.

aP2 - end point of the rhumbline segment.

aP3 - point from which the shortest distance to the line segment is sought.

aRadius - the radius of the sphere on which to perform the calculation.

aRelativeTolerance - relative tolerance.

aAbsoluteTolerance - absolute tolerance.

aResultSFCT - contains the point on the rhumbline segment that is the shortest from point aP3.

Returns:

the geodesic distance from point aP3 to the rhumbline segment aP1-aP2 (meters).

rhumblineDistance3D

public static double rhumblineDistance3D(ILcdPoint aPoint1,
                                         ILcdPoint aPoint2,
                                         double aRadius)

Calculates the rhumbline distance to go from point p1 to point p2. Unlike TLcdSphereRhumblineUtil#rhumblineDistance, which ignores the height of the points, the distance calculations of this method take the heights of the given points into account.

Parameters:

aPoint1 - the start (geodetic) point

aPoint2 - the end (geodetic) point

aRadius - the radius of the sphere on which to perform the distance calculation

Returns:

the 3D distance of the line segment formed by aPoint1 and aPoint2

Since:

2022.1