I doubt that phone + battery + solar charger is going to weigh less than a compass and a few sheets of waterproof maps. Since you have to resupply at points along the trail, you don't need to carry detailed maps for the entire route in your pack.
I personally wouldn't want to rely 100% on a phone. It would have to be ruggedized, you would need a way to charge it daily, and it would have to have all the maps (which for this purpose are detailed topographic maps) stored locally, as there is no cell coverage in a lot of wilderness areas.
Most of the time on the PCT, maps are superfluous. The trail is well defined with clear signs. Even so, it's always a good idea to pay attention to where you are and what the area around you is like. If something goes wrong (injury, medical emergency, wrong turn at Albuquerque), that knowledge could save someone's life.
I personally wouldn't want to rely 100% on a phone. It would have to be ruggedized, you would need a way to charge it daily, and it would have to have all the maps (which for this purpose are detailed topographic maps) stored locally, as there is no cell coverage in a lot of wilderness areas.
Most of the time on the PCT, maps are superfluous. The trail is well defined with clear signs. Even so, it's always a good idea to pay attention to where you are and what the area around you is like. If something goes wrong (injury, medical emergency, wrong turn at Albuquerque), that knowledge could save someone's life.