Finally, the maps included with your GPS navigation units
, including portable GPS systems are important to consider when making a purchase. Many systems include pre-loaded maps for the United States- and may include other countries as well. When you choose a portable GPS or a permanent GPS navigation receiver made by one of the larger manufacturers, like Garmin or TomTom, you may also be able to receive free upgrades for maps, that include new roads or construction changes as well as current data for the point of interest database to help you find restaurants, gas stations and other businesses on your travels.