I know that having WiFi turned on makes the GPS positioning better and more accurate.
What I have also found is that, when I get in a heavily populated area, my phone will automatically jump from WiFi connection to WiFi connection. When this happens, pokestops don't always work properly. I will get a blank circle, and nothing happens when I spin.
I keep WiFi on when playing in my rural neighborhood, (There's only 1 pokestop within a mile of my house), but if I go to my favorite pokestop area where there are 18 stops in a 5 block span full of both businesses and residences, I have to turn WiFi off in order to get the maximum out of my walk. Has anyone else noticed this?
Turning it off prevents so many freezes I keep it permanently off when playing. The local phone networks are bad enough as it is - holding a 3G or better network connection for any length of time can be problematic.
I suspect a lot of player's frustrations are more down to the app demanding a stable high speed data connection, than app bugs.
Android or iOS? On iPhone there is an option in WiFi settings "Ask to join networks". I have this turned off and I don't join public WiFi networks unless I am going to be sitting at a place for a long time. I have to manually sign onto a network, and then I "Forget this network" when I am done.
I don't like automatically signing into public networks because it will frequently interrupt my internet traffic for up to 10s (first world problems) when it connects and again when it disconnects. If I am just walking by a place, I do not want that. Even more so with some free public WiFi like Starbucks or McDonalds which will use the same router name at different locations (so you will automatically connect if you have used any of their networks), but require you to go to your web browser and agree to the terms of service before you can get any data transfer.
