Memory for GPS-based golf distancing system

A portable distance tracking system for use by a player on a playing field wherein the playing field includes at least a first landmark and wherein the system comprises at least one mobile interface unit. The mobile interface unit includes a memory element, position interface electronics, a data processor, and a player interface. The memory element stores digitized map representations of playing fields. The position interface electronics receive position indicative signals from and external source, wherein the position indicative signals are representative of a geographical location of the mobile interface unit. The data processor couples to the memory element and to the position interface electronics and correlates the geographical location to a field location of said mobile interface unit on said playing field. The processor also determines the distance from the mobile interface unit to the first landmark. The player interface is coupled to the data process and communicates the distance between the mobile interface unit and the first landmark to the player. According to a preferred embodiment, the playing field is a golf course and the first landmark is a flag location at a select hole on the golf course.