Marshall Islands Stick Chart

Stick charts are traditional Marshallese navigational aids made from coconut midribs, sennit fiber and shells that encode the patterns of ocean swells and the ways islands disrupt them. Rather than plotting positions to be consulted en route, the charts were studied and memorized beforehand; navigators then relied on bodily sensations - feeling the canoe's pitch and roll - to detect swells and the "shadow" of islands. Individual charts varied widely and were often only fully interpretable by the maker. The practice declined after World War II with the spread of electronic navigation, reduced inter-island canoe travel, and cultural disruption from nuclear testing. The charts are significant to the history of cartography because they map dynamic ocean processes rather than landforms, demonstrating a distinct, non-Western system for encoding spatial and physical maritime information.

Marshallese recognized four principal swells - rilib (the strong, year-round “backbone” from the east), kaelib (weaker, year-round), bungdockerik (southwest swell, sometimes as strong as rilib in southern islands), and bundockeing (weakest, felt mainly in the north) - and represented their directions and refraction around islands with curved sticks and threads. Stick charts fall into three types: mattang (abstract instructional models), meddo (local charts showing islands, swell directions, curvature, intersections and detection distance for a section of a chain), and rebbelib (comprehensive charts covering most or entire island chains). Knowledge was restricted - typically passed father to son - and long voyages used squadrons led by pilots skilled with the charts; Western documentation began in the 19th century, notably by missionaries and a German naval officer.