This may not look like a map, but it is indeed a nautical chart from Micronesia. Most such maps were made of pandanus sticks and cowry shells. Sticks represent currents, wind and wave patterns; shells represent landforms, atolls and reefs.
Stick and shell maps contained jealously guarded secrets of an ancient "brotherhood" of master navigators. The charts were not taken along on sea voyages, but instead were studied and memorized by the navigators who set sail on explorations across vast open stretches of the Pacific ocean.
Nowadays, National Oceanic & Atmospheric Administration (NOAA) Electronic Navigation Charts (ENCs) are available online almost anywhere in the world.