Package com.luciad.geodesy

Class 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 Details

    • 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:

    • 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

      @Deprecated public static double closestPointOnShape(ILcdPoint aPoint, ILcdShape aShape, ILcd2DEditablePoint aResultSFCT)
      Deprecated.
      Use closestPointOnShape(ILcdPoint, ILcdShape, double, ILcd2DEditablePoint), which takes the sphere radius explicitly.
      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 method supports rhumb and geodesic ILcdPolyline and ILcdPolygon instances, as well as ILcdCircle and ILcdPoint instances. ILcdShapeList and ILcdComplexPolygon instances are unwrapped, and the closest point over all of their parts is returned.

      Polygons and circles are treated as their boundary (outline), not as a filled area: for a point inside a polygon or circle, the distance to its boundary is returned.

      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)

      This method uses a default absolute tolerance of 1.0 (meters) and a default relative tolerance of 1e-10.

      The distance is returned in meters measured on a sphere of radius TLcdConstant.EARTH_RADIUS. Use closestPointOnShape(ILcdPoint, ILcdShape, double, ILcd2DEditablePoint) to measure on a sphere of a given radius.

      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 in meters, on a sphere of radius TLcdConstant.EARTH_RADIUS
      Throws:
      IllegalArgumentException - if the provided shape is not supported

    • closestPointOnShape

      @Deprecated public static double closestPointOnShape(ILcdPoint aPoint, ILcdShape aShape, double aRelativeTolerance, double aAbsoluteTolerance, ILcd2DEditablePoint aResultSFCT)
      Deprecated.
      Use closestPointOnShape(ILcdPoint, ILcdShape, double, double, double, ILcd2DEditablePoint), which takes the sphere radius explicitly. This overload measures on a sphere of TLcdConstant.EARTH_RADIUS.
      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 method supports rhumb and geodesic ILcdPolyline and ILcdPolygon instances, as well as ILcdCircle and ILcdPoint instances. ILcdShapeList and ILcdComplexPolygon instances are unwrapped, and the closest point over all of their parts is returned.

      Polygons and circles are treated as their boundary (outline), not as a filled area: for a point inside a polygon or circle, the distance to its boundary is returned.

      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)

      The distance is returned in meters measured on a sphere of radius TLcdConstant.EARTH_RADIUS. Use closestPointOnShape(ILcdPoint, ILcdShape, double, double, double, ILcd2DEditablePoint) to measure on a sphere of a given radius.

      Parameters:
      aPoint - the starting point
      aShape - the shape for which to find the point closest to aPoint
      aRelativeTolerance - relative tolerance (w.r.t. the parts that make up the shape, like a segment of a polyline).
      aAbsoluteTolerance - absolute tolerance (in meters).
      aResultSFCT - side-effect parameter for the resulting point
      Returns:
      the shortest distance in meters, on a sphere of radius TLcdConstant.EARTH_RADIUS
      Throws:
      IllegalArgumentException - if the provided shape is not supported
      Since:
      2026.1

    • closestPointOnShape

      public static double closestPointOnShape(ILcdPoint aPoint, ILcdShape aShape, double aRadius, ILcd2DEditablePoint aResultSFCT)
      Finds the shortest rhumb distance from the given point to the given shape, measured on a sphere of the given radius. The corresponding point on the shape is returned in the side effect parameter.

      This method supports rhumb and geodesic ILcdPolyline and ILcdPolygon instances, as well as ILcdCircle and ILcdPoint instances. ILcdShapeList and ILcdComplexPolygon instances are unwrapped, and the closest point over all of their parts is returned.

      Polygons and circles are treated as their boundary (outline), not as a filled area: for a point inside a polygon or circle, the distance to its boundary is returned.

      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)

      This method calls closestPointOnShape(ILcdPoint, ILcdShape, double, double, double, ILcd2DEditablePoint) with a default relative tolerance of 1e-10 and a default absolute tolerance of 1.0 (meters).

      Parameters:
      aPoint - the starting point
      aShape - the shape for which to find the point closest to aPoint
      aRadius - the radius of the sphere on which to perform the calculation (meters)
      aResultSFCT - side-effect parameter for the resulting point
      Returns:
      the shortest distance in meters
      Throws:
      IllegalArgumentException - if the provided shape is not supported
      Since:
      2026.1.01

    • closestPointOnShape

      public static double closestPointOnShape(ILcdPoint aPoint, ILcdShape aShape, double aRadius, double aRelativeTolerance, double aAbsoluteTolerance, ILcd2DEditablePoint aResultSFCT)
      Finds the shortest rhumb distance from the given point to the given shape, measured on a sphere of the given radius. The corresponding point on the shape is returned in the side effect parameter.

      This method supports rhumb and geodesic ILcdPolyline and ILcdPolygon instances, as well as ILcdCircle and ILcdPoint instances. ILcdShapeList and ILcdComplexPolygon instances are unwrapped, and the closest point over all of their parts is returned.

      Polygons and circles are treated as their boundary (outline), not as a filled area: for a point inside a polygon or circle, the distance to its boundary is returned.

      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
      aRadius - the radius of the sphere on which to perform the calculation (meters)
      aRelativeTolerance - relative tolerance (w.r.t. the parts that make up the shape, like a segment of a polyline).
      aAbsoluteTolerance - absolute tolerance (in meters).
      aResultSFCT - side-effect parameter for the resulting point
      Returns:
      the shortest distance in meters
      Throws:
      IllegalArgumentException - if the provided shape is not supported
      Since:
      2026.1.01

    • closestPointsBetweenShapes

      public static double closestPointsBetweenShapes(ILcdShape aShape1, ILcdShape aShape2, double aRadius, List<TLcdLonLatLine> aResultSFCT)
      Finds the shortest rhumb distance between two shapes, measured on a sphere of the given radius, and the connecting segment(s) that realize it. The distance is returned in meters and each connecting segment is a TLcdLonLatLine.
      Connecting segments between two shapes

      See TLcdEllipsoidUtil.closestPointsBetweenShapes(ILcdShape, ILcdShape, ILcdEllipsoid, List) for the full contract, the supported shape types, the result-list semantics (typically one segment, more for touching, tied or continuum configurations) and the documented limitations.

      This method calls closestPointsBetweenShapes(ILcdShape, ILcdShape, double, double, double, List) with a default relative tolerance of 1e-10 and a default absolute tolerance of 1.0 (meters).

      Parameters:
      aShape1 - the first shape
      aShape2 - the second shape
      aRadius - the radius of the sphere on which to perform the calculation (meters)
      aResultSFCT - side-effect parameter that receives the connecting segment(s); cleared first
      Returns:
      the shortest rhumb distance (meters)
      Throws:
      IllegalArgumentException - if either shape is of an unsupported type
      Since:
      2026.1.01

    • closestPointsBetweenShapes

      public static double closestPointsBetweenShapes(ILcdShape aShape1, ILcdShape aShape2, double aRadius, double aRelativeTolerance, double aAbsoluteTolerance, List<TLcdLonLatLine> aResultSFCT)
      Finds the shortest rhumb distance between two shapes, measured on a sphere of the given radius, and the connecting segment(s) that realize it, to within the given tolerances. See closestPointsBetweenShapes(ILcdShape, ILcdShape, double, List) and TLcdEllipsoidUtil.closestPointsBetweenShapes(ILcdShape, ILcdShape, ILcdEllipsoid, List) for the full contract and the documented limitations.
      Parameters:
      aShape1 - the first shape
      aShape2 - the second shape
      aRadius - the radius of the sphere on which to perform the calculation (meters)
      aRelativeTolerance - relative tolerance (w.r.t. the parts that make up the shapes)
      aAbsoluteTolerance - absolute tolerance (in meters)
      aResultSFCT - side-effect parameter that receives the connecting segment(s); cleared first
      Returns:
      the shortest rhumb distance (meters)
      Throws:
      IllegalArgumentException - if either shape is of an unsupported type
      Since:
      2026.1.01

    • 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