You got lost in a canyon with no signal? That's so scary! I always worry about my phone dying when I'm out hiking. Paper maps really are a lifesaver for places like that. Your story makes me want to go buy one right now.
I got stuck in a remote area once with a dead phone. Having a physical map and a cheap compass from my backpack was key. I marked my starting point and major trail junctions in pencil as I went. That way, even when I got turned around, I could trace my steps back.