Abstract: A GPS tuner provides high precision measurement, mapping, and Geocaching tools for a pocket PC and other mobile computing devices. The tuner accepts waypoints defining a desired route for navigation by a user, including land, water, and air routes. Waypoints comprise latitude, longitude, and altitude of a geographical coordinate; user-assigned names; a type of geographic coordinate and coordinate description; photos; and associated sounds. Waypoints are inputted by a user keying in way point data; by copying waypoints from another stored route; internet downloading from a Geocaching file; or importing from a GPX file. Waypoints are also established from a free-form hand-drawn route on a touch screen, which display a world-wide digital elevation model, and upon which a user scanned map is overlaid through a calibration process. Navigation functions are selectable from a touch screen display of a self-adapting, ergonomically configured, array of icons.