GeographicLib is a small C++ library for: geodesic and rhumb line calculations; conversions between geographic, UTM, UPS, MGRS, geocentric, and local cartesian coordinates; gravity (e.g., EGM2008) and geomagnetic field (e.g., WMM2020) calculations.
BrainBox is a simulation toolbox, similar to MatLab, that simulates physical and mathematical models remotely via WebServices. BrainBox provides a user interface to help create the diagrams and interact with the simulation results with a built-in languag