<Table> <Tr> <Td> </Td> <Td> This article includes a list of references, but its sources remain unclear because it has insufficient inline citations . Please help to improve this article by introducing more precise citations . (February 2012) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article includes a list of references, but its sources remain unclear because it has insufficient inline citations . Please help to improve this article by introducing more precise citations . (February 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> Stick charts were made and used by the Marshallese to navigate the Pacific Ocean by canoe off the coast of the Marshall Islands . 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 . </P> <P> The stick charts are a significant contribution to the history of cartography because they represent a system of mapping ocean swells, which was never before accomplished . They also use different materials from those common in other parts of the world . They are an indication that ancient maps may have looked very different, and encoded different features from the earth, than the maps we use today . </P>

What did the marshall islanders use stick charts for until the 1950s