Also, if your phone is utilizing the GPS, it will chew up battery life big time. My guess is if you are on the trail 16 hours, your phone will have discharged totally well before you ordering your cheeseburger and fries at the WPS.
I don't see the utility of this product.
I don't see the utility of this app either for the Main Trail, unless you were in a whiteout. I can't imagine anyone staring at a screen during their climb, but just having it on the phone they are carrying anyway might give someone comfort. The JMT app may have some appeal to me as an interesting add to my Android. Wouldn't substitute it for a real map though.
Regarding battery life, here's a good gadget to know about.
A $30 (Amazon) 4 ounce Lithium-ion battery pack with USB output, can charge your phone about 3 times or your iPod several times. Looks like a good solution to keep the iPod going up all those JMT passes. I only turn on my phone maybe once a day if I have reception, or if I were to need the GPS.
