linguistic:voice_change, structural:reformatting
Recording wave and swell formation in navigational devices

The people of the Marshall Islands have a history of using stick charts, to serve as spatial representations of islands and the conditions around them; with the curvature and meeting-points of the coconut ribs indicating the wave motion that was the result of islands standing in the path of the prevailing wind and the run of the waves. The charts represented major ocean swell patterns and the ways the islands disrupted those patterns, typically determined by sensing disruptions in ocean swells by islands during sea navigation. Most stick charts were made from the midribs of coconut fronds that were tied together to form an open framework. Island locations were represented by shells tied to the framework, or by the lashed junction of two or more sticks. The threads represented prevailing ocean surface wave -crests and directions they took as they approached islands and met other similar wave-crests formed by the ebb and flow of breakers. Individual charts varied so much in form and interpretation that the individual navigator who made the chart was the only person who could fully interpret and use it. The use of stick charts ended after World War II when new electronic technologies made navigation more accessible and travel among islands by canoe lessened.