determine location iphone

from what i read i understand that iPhone can determine your location using Wi-Fi. If you're not in range of any Wi-Fi, iPhone can determine your location using cellular towers.

I am currently develop app th开发者_StackOverflowat use the GPS so my question is when there is no GPS signal (like in buildings)does the location services try automatic to determine the position through Wifi or cellular towers OR i need to do somthing manualy in the code??

if it does automatic does it return a GPS format(latitude, longtitude) or somthing else?

thanks so much.

It will return a position as always, but with reduced accuracy.