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.
A cartography program with parameter adjustments and gravity fonctions
...The input data is point data (not lines or areas) using csv files with object names (cities), variables (e.g. birth rate) and x and y coordinates. It is also possible to import maps in GeoJSON format. Possible output maps are: proportional circles, colour classes and interaction potential functions (Gravity models). Test data (10 countries and associated data) is provided with the program and located in the installation directory
A user manual is also provided.