Editing Polar coordinate system (section)

===Position and navigation===
Polar coordinates are used often in [[navigation]] as the destination or direction of travel can be given as an angle and distance from the object being considered. For instance, [[aircraft]] use a slightly modified version of the polar coordinates for navigation. In this system, the one generally used for any sort of navigation, the 0° ray is generally called heading 360, and the angles continue in a clockwise direction, rather than counterclockwise, as in the mathematical system. Heading 360 corresponds to [[magnetic north]], while headings 90, 180, and 270 correspond to magnetic east, south, and west, respectively.<ref>{{Cite web |last=Santhi |first=Sumrit |title=Aircraft Navigation System |url=http://www.thaitechnics.com/nav/adf.html |access-date=2006-11-26}}</ref> Thus, an aircraft traveling 5 nautical miles due east will be traveling 5 units at heading 90 (read [[ICAO spelling alphabet|zero-niner-zero]] by [[air traffic control]]).<ref>{{Cite web |title=Emergency Procedures |url=https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-7of7.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130603111635/http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-7of7.pdf |archive-date=2013-06-03 |access-date=2007-01-15}}</ref>