This app was mentioned in 2 comments, with an average of 1.00 upvote
This was in jest. Honestly, the accelorometer and magnetic compasses within our phones can do an equally accurate job (RockLogger is one example App built for it).
Rocklogger. I've seen someone make a custom plastic clipboard that I could put all over wet slopes and into cracks with a swivel and then log all their discontinuities and their locations with the device GPS. Pretty cool.
https://play.google.com/store/apps/details?id=com.rockgecko.dips