When you use your Garmin, it receives satellite signals about your location. Your location is provided by the global positioning system, but it is not related to your position in the street grid. This information is irrelevant for the global positioning system satellites whether you walk down a one way street. For the satellite you are just a speck moving in relation to its last position. Yes, Garmin offers free map updates. You can. Follow the following steps. To get a free map update on Garmin.
