Pretty much completely not true.

If you shut off the cellular connection (ie. data) and you run your map program, it will still record your position but you won't have a map to display the track against. There is no requirement that you need to have data to use GPS. It is true that the phones use a database of wifi network's geographical locations to speed a GPS fix, but it is not a necessary requirement to have any data to have GPS work. There are also mapping applications that store maps internally to the phone where you can use them to navigate even where there is no data network available. Garmin has a number of these and I have used them successfully in just that manner.

FWIW, you can also store a google map on your phone in the google maps application to be used without network access (airplane mode). According to the link, the map will reside on your phone for 30 days.

I have also ridden my bike using Cyclemeter in areas devoid of cellular coverage. The app faithfully stores my track and data and displays it on a grid. There is, of course, no base map behind it, but it's easy to see where I've been and if a route has been loaded, where I'm going.



J.