Geo::CheapRuler A collection of very fast approximations to common geodesic measurements. Useful for performance-sensitive code that measures things on a city scale (less than 500km, not near the poles). Can be an order of magnitude faster than Haversine based methods. A Perl port of Mapbox's cheap-ruler v4.0.0 https://github.com/mapbox/cheap-ruler Very fast as they use just 1 trig function per call. The Maths model is based upon the Earth's actual shape (a squashed sphere). For 'city' scale work, it is more accurate than the Haversine formulae (which uses several trig calls based upon a spherical Earth). The Cheap\_Ruler Github page explains it better! See: https://github.com/aavmurphy/CheapRuler/REAME.md INSTALLATION To install this module, run the following commands: perl Makefile.PL make make test make install SUPPORT AND DOCUMENTATION After installing, you can find documentation for this module with the perldoc command. perldoc Geo::CheapRuler https://github.com/aavmurphy/CheapRuler https://github.com/mapbox/cheap-ruler You can also look for information at: Issues https://github.com/aavmurphy/CheapRuler/issues https://github.com/mapbox/cheap-ruler/issues LICENSE AND COPYRIGHT The original software is (c) Mapbox This port is Copyright (c) 2025 by Andrew Murphy. This is free software, licensed under: The Artistic License 2.0 (GPL Compatible)