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.
Extended Tcl (TclX) is an extension to Tcl, the Tool Command Language invented by Dr. John Ousterhout. Tcl is a simple and powerful embeddable programming language. Extended Tcl is oriented toward system programming tasks and large application development. TclX provides additional interfaces to the operating system. It also adds many new programming constructs, text manipulation tools, and debugging tools.
Tcl provides a portable scripting environment for Unix, Windows, and Macintosh that supports string processing and pattern matching, native file system access, shell-like control over other programs, TCP/IP networking, timers, and event-driven I/O. Tcl has traditional programming constructs like variables, loops, procedures, namespaces, error handling, script packages, and dynamic loading of DLLs. Tk provides portable GUIs on UNIX, Windows, and Macintosh. A powerful widget set and the concise scripting interface to Tk make it a breeze to develop sophisticated user interfaces.