I was in Scotland with a Canadian phone recently, and to avoid roaming charges I had my cellular data turned off throughout the trip. However, the pictures I took still had accurate geotags, meaning my location was still available to my camera apps (even though I couldn't actually see these locations on a map until I got home).
My question is: how would I go about retrieving location data in a situation like that, where I can't actually display a map because there is no internet connection? And, just to improve my understanding, how is the location actually being retrieved? If "cellular data" is off, is GPS still available, or can the location only be calculated using nearby wi-fi hotspots at that point? And finally, if both cellular data AND wi-fi is turned off on a device, can location still be retrieved (i.e. is GPS still active)?
Any info on the subject is welcome - all I am trying to do is handle all possible situations created by the presence or lack of location services and an internet connection in an app where I (if possible) display and store the user's location.
iOS devices that have actual GPS hardware in them can give accurate location data even if there is no WiFi or cellular.
Of course, most map apps require an Internet connection to display a map. But if you have a map app with local map data, then you would be able to see the map with your position even without any Internet connection.
On devices with an actual GPS, location services works just fine with no Internet. It may take a little longer to zero in on your position but it still works normally. Of course on iOS devices with no real GPS, you do need a cellular or WiFi signal to get any position data.