Originally Posted By: comms

I have been underwhelmed to say the least regarding actual GPS apps, free or charged. Also, as I understand, they work off the 3G network and not satellite so if I am out of cell tower range, its useless anyway. If this is incorrect let me know.

This has also kept me away from trail/hike apps. Change my mind if you can.


The GPS is satellite-based GPS just like any Garmin device. It is not in any way dependent on cell towers. If you're using the GPS functions of the iPhone, you're using the satellites.
In urban areas where there is poor line of sight to the sky, some applications (google maps) fall back to positional estimation based on cell towers and their known coordinates.

In terms out use in outdoors situations, the iPhone is a fair substitute for a dedicated GPS device, but nowhere near rugged enough for serious use. Battery life is an issue and the lack of a replaceable battery means that even with a charging system of some kind, you're not going to have the same level of reliability as you would with a dedicated GPS device.