Boule is Python library for representing reference ellipsoids, calculating their gravity fields, and performing some global coordinate conversions. "Boule" is also French for "ball" as well as a traditional shape of bread resembling a squashed ball. Documentation: https://www.fatiando.org/boule Source code: https://github.com/fatiando/boule Part of the Fatiando a Terra project. Note: Authors are listed in alphabetical order by last name.