It was easiest and most accurate, for the Polynesians, to do astronomical navigation. The stars were classified after their movements over the sky, and they were named after the islands, they were leading to.

If they were sailing towards the Equator, it was easy to be accurate in the navigation, because the stars there move vertical. The farther you move towards the poles, the more complicated the navigation gets, and you will have to use several different constellations.