[Geographiclib-announce] GeographicLib 2.6 (released 2025-09-30)

[Charles K. <cha...@gm...>]

Changes between 2.6 (released 2025-09-30) and 2.5.2 versions:

    * Support for triaxial ellipoids. This is all placed in the
      GeographicLib::Triaxial namespace with the header files in the
      GeographicLib/Triaxial directory. This provides
      + Triaxial::Ellipsoid3 supports basic conversions of ellipsoidal
        coordinates.
      + Triaxial::GeodesicLine3 and Triaxial::Geodesic3 solve the direct
        and inverse geodesic problems on a triaxial ellipsoid. This
        implements Jacobi's solution for the direct problem. The inverse
        problem extends the method for solving the inverse problem on a
        biaxial ellipsoid.
      + Triaxial::Cartesian3 performs conversions between different
        systems of triaxial coordinates.
      + Triaxial::Conformal3 implements Jacobi's conformal projection for
        a triaxial ellipsoid. This allow a triaxial ellipsoid to be
        conformally mapped to a sphere or to any other ellipsoid.
      + Geod3Solve is a command-line utility offering access to
        Triaxial::Geodesic3.
      + Cart3Convert is a command-line utility offering access to
        Triaxial::Cartesian3.
      + Conformal3Proj is a command-line utiity offering access to
        Triaxial::Conformal3.
      + Constants::Triaxial_Earth_a, Constants::Triaxial_Earth_b,
        Constants::Triaxial_Earth_c, and Constants::Triaxial_Earth_lon0
        specify a simple triaxial model for the Earth.
      + experimental::TriaxialGeodesicODE is provided to illustrate the
        solution of the direct geodesic problem by integrating the
        ordinary differential equations for the geodesic. Because this
        depends on Boost, this is not part of the GeographicLib library.
      + experimental/Geod3ODE.cpp a utility for doing direct geodesic
        calculations using experimental::TriaxialGeodesicODE.

    * To support the triaxial routines, the following classes have been
      added:
      + AngleT provides an accurate representation of angles of any
        magnitude. This might replace AuxAngle at some point.
      + Trigfun supports representing periodic functions as Fourier
        series with automatic selection of the number of terms to
        use. This offers a tiny subset of the functionality of the trig
        series in Chebfun. This might replace DST at some point.

    * C++17 is now required. Minimum version of Visual Studio supported
      is Visual Studio 15 2017.

    * Add Math::clamp.

    * Because experimental::TriaxialGeodesicODE depends on Boost, the
      CMake option USE_BOOST_FOR_EXAMPLES has been renamed
      USE_BOOST. This will cause find_package(Boost) to be called, but
      does not affect how the library or the tools are built.


-- 
Charles Karney <ka...@al...>
702 Prospect Ave
Princeton, NJ 08540-4037