If you’re looking for a free GPS navigator, Navit might be the answer. This is a car navigation system with a routing engine and a modular design, that relies on vector maps in all sorts of formats.
You’ll even be able to use multiple maps at one time and you should know that Navit relies on GTK+ or SDL user interfaces, perfect for touchscreens. Points of interest are also supported, as well as the current vehicle position (read from gpsd or via the NMEA GPS sensors).
The software’s routing engine will calculate the perfect route in order to reach the desired destination, plus it’ll generate directions and provide audio support in 24 languages. You can download the freeware alpha version of Navit from here.