Micronesian stick charts show wave patterns and currents. The shells represent atolls and islands. Using stick charts (also called rebbelibs, medos, and mattangs) ancient mariners successfully navigated thousands of miles of the South Pacific Ocean without compasses, astrolabes, or other mechanical devices.
Ancient mariners from Majõl (The Marshall Islands) developed “stick charts” to understand the vast Pacific Ocean. The charts aren’t made of sticks. Most stick charts are made of coconut fiber and shells. Placement of the fibers and shells indicate the location of islands, waves, and currents.
Stick charts were not used for navigation in the way we use maps or charts today. In fact, the Marshallese probably did not consult stick charts on their long journeys throughout Micronesia. Navigators memorized the chart before the journey was made.
Charts were highly individualized. Sometimes, a stick chart could only be read by the person who made it! Still, there are some standard features used to interpret ocean features.
The stick charts are the earliest known system of mapping ocean swells in the world. Use of stick charts and navigation by swells apparently ended after World War II, when the Marshallese way of life was radically altered by US occupation and nuclear weapons testing.