GPS without data?
 

Has anyone actually tried using their phone's GPS without having data or wifi turned on? I know many phones have an actual GPS receiver, but they also use AGPS as their primary source to get an accurate fix. Has anyone tried downloading a map, then taking the phone offline completely and just activating the GPS? How did that work in a city - is it fairly accurate?

Worked fine on my iphone in Hawaii, had data turned off as I'm Canadian, downloaded the route I had to drive via wifi in the hotel, then as we were driving my SO was looking at the GPS tracker signal in google maps and told me where to turn. It lags a bit, bit not more than like 100m at most. Worked fine. Accurate in a city as long as you're not speeding, we also used it in San Francisco as we were walking/biking.

So you did use it walking in the city. That is my big concern, as getting a GPS signal amongst buildings I would imagine being hard.

The GPS on my Android or iOS device is usually enough if buildings aren't too dense and high. Android can also use an external bluetooth logger
https://play.google.com/store/apps/d...id.btgps&hl=en

I have a Holux unit for geotagging photos and it does maintain signal in dense urban pedestrian situations decently.

like I said, walking in San Francisco it was fine. Though to be fair, San Francisco isn't the densest city, so it's no NYC or anything, but I had no troubles.

Had offline city maps downloaded on iPhone 5s and LG's Nexus 5, used them both in Taiwan and in South Korea (Incheon & Seoul) with good results in driving (well, backseat passenger) mode - didn't try walking around holding it up, LOL. It was pretty accurate, AFAIK - without turning on cellular data, free roaming or otherwise.

The GPS on my Note 2 works in airplane mode in flight (no WiFi on the plane either), so I would assume that it also would work on the ground.

Love knowing exactly where we are in flight, and watching the blue dot motor along on the map.

I use Maps.Me (with open source maps for almost any nation) on an Android phone, and it works fine without data connection. Like Bonehead (above), I use it on a plane.

I use Navigon on my iPhone all the time when in Canada with data turned off completely since the maps are stored on the phone. It works great.