SaVi is satellite visualization software that lets you create, run, examine, and modify satellite orbits in two and three dimensions. Simulations of Iridium, Globalstar, Galileo, GPS, and other satellite constellations are included. SaVi requires Tcl and Tk on a system with Unix libraries. SaVi works well with the 3D renderer Geomview. Geomview is optional, though recommended for its 3D rendering capabilities.
Viking is a GTK2-based GPS data editor and viewer. It can download and show OpenStreetMaps, Terraserver, and other maps, import and draw tracks and waypoints over them, add coordinate lines, make new tracks and waypoints, hide different things, and more. It uses a hierarchical layering system to organize GPS data, maps, and other layer types with spatial data (such as coordinate lines).
GetDP is a general finite element solver using mixed elements to discretize de Rham-type complexes in one, two, and three dimensions. The main feature of GetDP is the closeness between the input data defining discrete problems (written by the user in ASCII data files) and the symbolic mathematical expressions of these problems.
QGolf was developed for radio amateurs to clarify the behaviour of a signal on an antenna. It demonstrates the forces that act on a rope if you move one end of it: you can see how waves are reflected, how resonance occurs, and how multiple pulses coexist on the same rope. Various parameters can be updated during the simulation.