Originally Posted by
Nihilum
Most modern smart phones do not download maps as they go...the information is stored on the device.
Phones can do this but you have to download the maps expliciitly (and each mapping app has its own method for doing that). Most mapping programs will store small amounts (cache) of map data but most of them (including the standard ones) get map data as needed.
Originally Posted by
Nihilum
The phone itself gets GPS location through triangulating through multiple terrestrial towers...it's not using data.
"GPS" is using GPS satellites: it works even when there are no cell towers.
Cell phones can also get positioning data from cell towers and wifi hot spots to "assist" the GPS positioning signal. GPS is more accurate but it can take a while to get the position at first (after being turned-on). The phones can also use this other positioning data when GPS is unavailable (like indoors). You'll see this technique listed as "assisted GPS" or "aGPS".
Originally Posted by
cplager
Most modern smart phones can store maps on the phone, but this is not the default behavior for Google maps (or Apple Maps) as far as I know.
Yes, they "can" do this.
It's not the default behavior for most apps (including the "standard" mapping programs). It appears that most of the apps require you to explicitly download the maps.
The apps provided by Garmin/TomTom/Sklobber/others might load the maps as part of their installation process.
But don't assume all or most of them do!
If you are getting maps by "magic", it's probably downloading them as needed (
you can test it by turning off cell/wifi access). It's not really possible to know how every app works but, if loaded maps are a feature that is important to you, you want to do some investigating to be sure how it works.