The Polynesian navigators used to be able to tell where they were to an amazing degree of accuracy by a combination of observations of skies, water temperature and color, wave patterns and sizes, current movements, types of fish, and many other aspects of their environment.
I would not be at all surprised if a primitive tribe still versed in some of these skills could not observe odd eddies or other very subtle ocean changes to give them enough warning to get to high ground.
Saw a "map" once, a complex curved pattern of woven sticks with various beads and items woven at points into the pattern. I had no idea what it meant, and it's possible that most ancient Polynesians wouldn't have either. Navigation methods were said to be closely guarded Guild secrets. See also: "Dune."
Whoa...check this out. Something very zen about this.
Space/Science » in reply to I wonder if this is how we will be/seem from an ETI encounter?
Ancient tribes