Why does my GPS use no data plan and my iPhone does for the same function?

[pilecarls8]

If I use my iPhone as a GPS, it consumes data... If I use my GPS unit, it's data free, yet they both do the same thing.

I'm looking at a cheaper plan that would use less data so I'm going thru each app and was just wondering why Google maps uses data and a GPS unit doesn't.

When I say GPS, it's a 8~10 year old device that I haven't used in a long time, but still works fine and requires no data plan.

I'm guessing it has to do with the directions being on device vs on Google's server.

[Boyd]

Your assumptions are all wrong here. Your phone has a gps chip inside, just like your dedicated GPS. It is perfectly capable of working without using any data at all. The reason that data is used is because of the app. There are other GPS apps that don't use data.

If you use something like Google Maps or Apple Maps, they receive all the mapping data over the cellular network and this is why data is being used. What you want is an app that contains all its own data.

You haven't said WHAT you are using the GPS for. Is it for navigation in the car (like Google Maps)? If so, you could have a look at the TomTom GoMobile app. It allows you to download maps of the whole world (if you want) or just of your local region. You would do this at home, over wifi. Once the maps are installed on your phone, no data will be used. Of course, you would need enough storage space on the phone to hold the maps.

https://www.tomtom.com/en_us/drive/gps-navigation/go-mobile/

When you use the app, if you want features such as realtime traffic, then that will use some data, but very little. You could also just turn that off. HERE (the same company that provides Garmin's maps) also has an app that (I think) can load everything on your phone.

https://wego.here.com/?map=32.05597,65.08903,3,normal

For outdoor use, there are a number of other apps that allow the data to be permanently installed on the phone. Locus Map, Orux Maps, Guru Maps, TwoNav, BackCountry Navigator and others have this capability.

In general, when choosing an app, the feature you should look for is usually called "offline maps"