App idea: Virtual reality for the blind

I have a friend that's blind, and he loves exploring outdoors, especially hiking. He once got lost in the forest with a friend of his. Fortunately, he has a cane, and sees better than most. He still had to lean on his friend for directions because they wouldn't be able get help on their phones because of no cell phone service. That spooked me into thinking, what if there's an app that lets you navigate through open spaces with your phone, using GPS, and location services, so you can find your way out?