Originally Posted by longjohn
The iPhone does have a real GPS receiver but in reality uses assisted GPS (AGPS) utilsing the GSM/3G & wifi networks to provide a quicker positional fix - so it does know exactly where you are (even without the assisted bit - just taking longer to find out). However it is entirely dependant on the internet for map tile data and therefore cannot show your position on a map without this connection - so it knows where you are but just can't put it on a map. This is certainly true for the built in mapping apps & Google maps - not sure if any of the navigational apps get round this by having a built in positional & map database or something....??
My iPhone has the maps in it and works just fine without GPRS, 3G, wifi or any other additives. You just need to download the maps. If you're operating in areas with no signal or being forced to use data roaming all the time then having the maps is essential. I have a 32 gig phone so there's plenty of space for map storage. A condom works fine for waterproofing, touch screen functionality and visibility. The addition of a "power monkey" style lithium battery will run apps for 24 hrs if your having to use boats with no 12v socket. If I bought another phone I would definitely have it professionally coated with a superhydrophobic nano structure.