# Talk:Chamberlin trimetric projection

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## which center?

"Unlike triangulation on a plane where three such compass circles will intersect at a unique point, the compass circles from a sphere do not intersect precisely at a point. A small triangle is generated from the intersections, and the center of this triangle is calculated as the mapped point."

A general triangle has multiple "centers"; which one? —Tamfang (talk) 23:04, 8 March 2011 (UTC)

According to the paper by Bretterbauer here, Chamberlin did not specify, since it was originally done by hand and eye. (Nor are they proper triangles since the edges are arcs, not line segments) --Belg4mit (talk) 01:42, 6 August 2011 (UTC)

## Use for Dymaxion map

Unless I'm misunderstanding something, this projection is the basis for the Dymaxion map - which divides the world into 20 equilateral triangles, and the Chamberlin trimetric is used to model each triangle (with the vertices as the three points of projection). Shouldn't this be mentioned in one or both places? 87.194.176.188 (talk) 17:19, 2 July 2011 (UTC)

Nope, the patent cited on the dymaxion map page clearly states the facets of the polyhedron are gnomonic projections. Both date to 1964 as well, so it would have been difficult (but not impossible) for one to inform the other. --Belg4mit (talk) 01:29, 6 August 2011 (UTC)
Although you could use it, since it would be an appropriate scale i.e; the dymaxion icosahedron splits Africa onto two facets versus the single map given as an example on this page. _-Belg4mit (talk) 01:49, 6 August 2011 (UTC)