Most GPS units come with maps already programmed into them, and you can subscribe to services that keep them updated. If you need to add additional maps to your GPS, however, you can download them from websites that offer free GPS maps. You may need to add new maps to your GPS if you live in or are planning to visit a remote area not well covered by standard maps. If you have had your GPS unit for some time, it might be time to update the maps.
Visit a website that offers free GPS maps. Such sites include OpenStreetMap, GMap-Track, GPSFileDepot and JDMCox Software, which offers USAPhotoMaps. Maps specifically for Garmin GPS devices can be found at MapCenter.
Download the maps. On OpenStreetMap, click "Export," then export it as "OpenStreetMap XML Data." On GMap-Track, register for free, then click "Download MGmaps." On GPSFileDepot, find the map you want by choosing your country and state and then clicking "Download." For USA Photo Maps, click "Download Here." For MapCenter, click "Browse All Uploaded Maps by Country, Region, and Category." Click on the country for which you want a map. Choose a region, then a category. Click "Binary IMG" to start your download.
Transfer the maps to your GPS unit. You can do this by connecting your GPS unit to your computer with a serial cable. Your GPS unit should have come with software to transfer the maps to the GPS. For example, Garmin units come with a program called MapSource. You can open it, load the maps from your computer and send them to your GPS. The USA Photo Maps does not need another program. You can open the application on your computer, go to the "GPS" menu and click "Send Maps."