Additional Eventually maps of the whole world will be converted to WGS84, a GPS standard datum. In the meantime, check to see that the GPS receiver recognizes the map datums used in your area, or areas you plan to travel to. All receivers will give you your latitude, longitude and altitude, but they don't all show you your location on a detailed map. When you're shopping for a receiver, decide what kind of map you'll need and make sure the receiver you purchase offers that type of map. Many receivers contain a general map for the world in memory, but this map may only show you major roads and bodies of water.
Some receivers have a wide array of other maps stored in memory or can download detail maps.
Some receivers accept special map cartridges with more detailed maps of specific areas. Some of the newer GPS receivers have download capability that allows you to download maps stored in your computer into your receiver. Your receiver will then guide you from way point to way point along your route. You can also plan routes on detailed maps before you leave for a trip, and record all the information you need on your hand-held receiver. Track Logging Receivers with a track logging feature can record your path as you move.