How GPS Maps Work

You need three things to navigate by GPS and they are (1) A network of satellites broadcasting the current time; (2) a receiver that can interpret the signal from several satellites to determine location, and (3) a digital zoomable map to display the current location and calculate routes to other locations.

Until recently the maps and routing information had to either (1) purchased as a complete package for Costa Rica from Garmin, Navsat etc. or (2) downloaded a bit at a time for the area of interest using a cell phone.

Option one was expensive with map and data package purchase. Option two could also be expensive because zoomable routing maps are big and phone data can be costly. Downloading was also unreliable because the most likely place to be lost (the middle of nowhere) was also the most likely place a phone would display no service. Now you can have the best of both worlds for free.

Most tablets and smart watches have built-in GPS receivers and now Google provides an excellent map and routing package for free download. Once you save the Google offline map package you can use your device to navigate even when there is no wifi or cell signal available.

GPS signals are on different frequencies and originate from satellites instead of towers so they will still come in strong even when you’ve got one bar. GPS signals are funded by U.S. taxpayers and there is no charge for receiving them.

Filed in: GPS

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