Talk:Marshall Islands stick chart

Fascinating
My word, this is interesting. Any pictures or diagrams of the charts that could be included in the article, along with explanations? And what is the amplitude, wavelength and velocity of the rilib, kaelib, etc. typically? What effect do the islands have on these? Shinobu (talk) 23:59, 19 June 2008 (UTC)
 * I've added some external links to the article - photographs and a scholarly article. Perhaps someone can try to obtain some of the photos for Wikipedia and/or use the article. Meanwhile we'll have to do with external links.. --Jashiin (talk) 12:08, 21 June 2008 (UTC)
 * Do you think it would be good to add the reqphoto request? 69.136.72.16 (talk) 22:47, 19 February 2010 (UTC)
 * Done. -- Quiddity (talk) 02:31, 19 April 2010 (UTC)

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Any citations on when stick charts were developed?
Should they be characterized as Polynesian broadly, or Marshall Islands specifically? I see them described in 1862, but there seems to be an implication they are in some way "ancient," implying development centuries or even millennia earlier. Is there any sourcing to help establish age? Thomas Craven (talk) 16:32, 12 January 2018 (UTC)


 * Iọkwe eok (Fond greetings) Mr. Craven. I am afraid characterization of these charts as Polynesian in any sense is mistaken. These are from the Marshallese people, uniquely, and Marshallese people are Micronesian rather than Polynesian. I am not aware of any citations as to the stick charts' age. See the work of Joseph Genz, especially his 2008 dissertation, for info on Marshallese navigational theory and techniques, including these stick charts. Seraphimek (talk) 03:41, 27 October 2018 (UTC)


 * I have found a list of publications by Joseph Genz but it does not include his 2008 one. One relevant one, from 2016, in this list is available online, and I have added it to the External Links. I have found a mention of the 2008 dissertation, but not been able to access it. FrankSier (talk) 09:00, 5 May 2020 (UTC)

Refraction or diffraction?
All sources for this article seem to agree on the term "refraction" for the effect of islands and shallow bathymetry on wave patterns. I don't believe that's correct usage. Refraction is the change in direction of a wave front as it passes through a 2D surface between two media of different refractive indices, such as with a lens or a water surface. Diffraction is the result of interference between a solid object and a wave in a fluid medium, such as the ring of sunlight seen around a coin blocking the Sun. Multiple objects such as two islands or the two slits in the double slit experiment create multiple wave patterns at angles to each other, which is what the stick charts appear to be depicting.

I'm not suggesting that Wikipedia change its terminology, only that the creators of the source material for this article, whoever they are, agree collectively to correct their terminology, without which we Wikipedia editors can do nothing. Vaughan Pratt (talk) 17:26, 7 February 2019 (UTC)


 * I'm not well-informed about the marine navigation system in Marshall Islands, but the terminology "refraction" used here and there could be correct. Wave speed becomes slow when the depth of water is close to the wavelength. This causes refraction near islands, where the water is shallow. You can see an experiment to show this phenomenon on Youtube, for instance: https://www.youtube.com/watch?v=QXaLLBFQdTY Ypako (talk) 13:19, 7 September 2022 (UTC)