View Full Version : Non "Polar" Polar Lines (graticules?)

07-22-2012, 05:04 PM
http://en.wikipedia.org/wiki/File:Diego-homem-black-sea-ancient-map-1559.jpg -- this is a fairly good example of what I'm talking about, since I don't know what these are called. (which made it hard to search the forums for them ;) I know they have something to do with the curvature of the earth and projecting that onto the flat 2d map, but I'm curious how you would determine the location of origin for these "poles" and how to use them for navigation etc.

07-22-2012, 05:10 PM
IIRC they're called "rhumb lines". There have been threads about that subject on this forum. You should try a search.

07-22-2012, 05:41 PM
Aha! thank you. that was exactly what I needed.