Implementation of geodesic routines in modern Fortran.

This is a library to solve geodesic problems on a planetary body (e.g., the Earth).

Some of the algorithms in this library:

See the latest API documentation for the full list. This was generated from the source code using FORD (i.e. by running ford ford.md).

A fpm.toml file is provided for compiling geodesic-fortran with the Fortran Package Manager. For example, to build:

fpm build --profile release

By default, the library is built with double precision (real64) real values. Explicitly specifying the real kind can be done using the following processor flags:

For example, to build a single precision version of the library, use:

fpm build --profile release --flag "-DREAL32"

To run the unit tests:

fpm test --profile release

To use geodesic-fortran within your fpm project, add the following to your fpm.toml file:

[dependencies]
geodesic-fortran = { git="https://github.com/jacobwilliams/geodesic-fortran.git" }

or, to use a specific version:

[dependencies]
geodesic-fortran = { git="https://github.com/jacobwilliams/geodesic-fortran.git", tag = "1.0.0"  }

• This library is licensed under a permissive MIT/X11/BSD license.

• T. Vincenty, "Direct and Inverse Solutions of Geodesics on the Ellipsoid with Application of Nested Equations", Survey Review XXII. 176, April 1975.
• C. F. F. Karney, Algorithms for geodesics, J. Geodesy 87(1), 43–55 (2013); Addenda.
• G. Panou and R. Korakitis, "Cartesian to geodetic coordinates conversion on an ellipsoid using the bisection method". Journal of Geodesy volume 96, Article number: 66 (2022).
• Gema Maria Diaz-Toca, Leandro Marin, Ioana Necula, "Direct transformation from Cartesian into geodetic coordinates on a triaxial ellipsoid", Computers & Geosciences, Volume 142, September 2020, 104551.

• Geographiclib documentation and git repository
• Fortran Astrodynamics Toolkit
• FORWARD and INVERSE from the NGS