If I’m giving bearings to a target or a destination, and, say, it’s due west of me…what “degrees” is that? I’m from a mathematics background, so east (positive x-axis) is zero, and thus west (negative x-axis) would be 180 degrees. Angles sweep out counter-clockwise, so north is 90 and south is 270.
But I bumped into a reference where a guy said, “Due west of here, 270 degrees.” I’m guessing that makes south zero – unless north is zero and the angles get swept out clockwise?
Is there a standard, say in the U.S. military? Do all NATO nations use the same reference angles?
The standard in the US is north is 0 degrees and they increase clockwise. I don’t know if that’s the standard in all NATO countries, but I’d assume so.
0 is north on charts and in a true bearing. In a relative bearing you bear an angle in degrees away from something such as another ship or object, landmark, navigational marking.
…and yes, the convention used a lot in mathematics is the one described by the OP. It just happens that North = 0 degrees, ascending clockwise, is the convention used in navigation – and land surveying, especially for very large scale (‘geodetic’) surveying.
(For smaller scale property surveys, bearings would probably be shown as, say, North 45 degrees, 15 minutes, 30 seconds West. Not meant to confuse, but just to show that there are several possible methods of showing directions.)
The key to any measurement is giving units and a reference. Sometimes in a given context the units and reference can be omitted because it is assumed that all participants know what they are.
A chart should state somewhere that all bearings are referenced to true north or magnetic north or some other reference.
In some situations 0º is referred to as 360º. When an aircraft is being vectored by ATC, they will not be told to turn on to a heading of “zero” but will instead be told a heading of “three six zero”.
By the way, this isn’t a criticism of the OP, I realise that people’s life experiences lead them to different levels of general knowledge, but I am surprised that the OP didn’t know this. I had thought it on the same level as knowing left and right.
Thank you, all: this was, in fact, totally new to me.
I came up from trig and calc, where (as I mentioned) zero is along the positive x-axis, and sweeps counter-clockwise. I never did any orienteering (although it sounds like jolly good fun, in a Boy Scouts sort of way!) When I give directions (which isn’t often) I use the old-fashioned nautical “North by West North-West” form. When telling someone how to cross the quad and find the old math building, it’s “straight ahead, through the archway, half-left, and look for the mural.”
Seriously, the issue of zero-degrees bearing, and which way the degrees increase, never came up in my life’s work.
(But I know exactly why e to the i pi + 1 equals zero!)
Yeah that’s all understood. Like I say, not a criticism, just a surprising reminder that people have vastly different experiences in their lives.
For what it’s worth I wouldn’t use 270º for West either, I probably wouldn’t even use West unless I had to (and I’d have to think about it), my internal compass doesn’t work that way.
I knew the convention. I’ll guess I first become aware of it in connection with airport runway designations! To fly from San Jose Airport (runway 30L: 300°, Northwest by West) to San Francisco Airport (28L) is a quick straight shot but the reverse trip requires two 180° turns — unless the wind changes and they reverse the runway directions (i.e. rename them 12R, 10R respectively).
I love maps and used to teach map reading to my wife’s Girl Guide Company. Many of these girls (11 to 16yo) were pretty hazy about direction. I don’t think that they teach them about geography in school anymore.
Some of them couldn’t see the relevance (and this was pre satnav), but quite a few, when taken to the top of a hill, with a 1" Ordnance Survey map and a compass were amazed to see how all those squiggly lines and funny symbols related to the countryside around them. Of course, they also grasped the essential difference between True North, Map North (ie the top of the map) and Magnetic North.
For a serious nit-pick (because I’m that much of a nautical-aviation-train geek!): Trinopus is wrong re “North by West North-West” as a direction. The direction he’s trying to specify is “Northwest by West”. You can remember that the three point names aren’t used in combination with the other directions and the Cardinal direction always comes last. Some people say I need to get a life, but I swear it’s around here somewhere; maybe it’s behind the couch.
For what it’s worth regarding 360 as a direction for runways: I went looking for a runway 36 by using Google Maps, even though I’m sure there are easier ways. Turns out Naval Air Station North Island, not too far from me, has a runway 36.
Runway 6 in Montreal is the one used by planes landing at an angle of approx 60 deg from due west. Runway 0 would be from due west. But of course, it would facing due east, so that is not definitive. And the numbers increase in the counter-clockwise direction. Actually, these are directions for a magnetic compass and occasionally a runway will change designation as the magnetic pole wanders.
At least two Montreal-area airports - Trudeau (CYUL) & Saint-Hubert (CYHU) - have runways designated 06. Both participate in the international standard whereby north is 0 (or 36) and headings increase clockwise. So so a plane landing on Runway 06 is headed northeast.
FWIW, US runways do not use the leading zero (IMHO they should) - that would be Runway 6 here, not 06. But it’s to the northeast no matter what. And there is no Runway 0 or 00 anywhere - if it’s within 5 degrees of magnetic (not true) North, it’s Runway 36. Unless it’s at an airport with 4 parallel runways in that direction, like Orlando, but I digress.