Posted on 06/22/2025 12:58:34 AM PDT by kawhill
The magnetic needle in a compass is attracted by the magnetism of the Earth, and therefore always points to the constantly shifting Magnetic North Pole. The Geographic North Pole is static and is located about 1200 miles north of the Magnetic Pole. Maps and directions are usually oriented toward the Geographic Pole, also referred to as "True North."
(Excerpt) Read more at usgs.gov ...
this has been mapped for hundreds of years...why is this posted?
Where I live if I want to travel north in the daytime I’ll use my compass, at night, the North Star. Not much of a problem starting out, but when I get near the top...a lot of miles in difference. Just a different topic on a public forum.
Maps often use “grid north.”
For instance, Universal Transverse Mercator — if you’re near longitude 6x + 3, with x an integer, true north and grid north will coincide. Otherwise they will differ slightly.
Albers is even worse — you need to be on 96 W for grid north to equal true north.
I like the topic...just surprised to see it. I had a little box compass years ago. Looked liked the same one that Einstein had.
so what is more accurate?
using a magnetic compass or tracking which side of a tree the moss grows on
Using a compass alone, for a hiker magnetic declination is not a factor. In the same way when using a map alone, is not a factor.
Once you start shooting compass bearings and then translating them to a map bearing, or the reverse, now you got a problem if declination is not compensated for. With say an 18 degree Easterly declination, the weary traveler might be off a mile from the intended point after traveling just a few miles.
It will be something to read again, after the poles flip.
Magnetic deviation from true north continues to be convenient for most people in the US despite a recent 30 years truly massive and very fast movement of the North Magnetic Pole from close to the north coast of Greenland near Canada all the way past the North Pole towards the Siberia coast.
From the US Eastern and Central Time Zones, that has little difference in deviation.
For far north Europe? Many degrees!
Maybe someone just now stumbled across topos.
Decent maps also have a declination diagram.
This is not news to any pilot anywhere - although GPS has changed the navigation game.
For some parts of the world, the declination changes have been significant in the last 40 years.
This is a basic subject for all people in the military.
Of course, GPS has made navigation much simpler, but in war zones, there is a lot of GPS jamming going on.
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There are large tracts in this Nation where maps cannot be delivered to a cell phone. The GPS location always comes through, right down to my paper maps. That saved my butt in Wyoming and Montana last summer.
Yeah. Had to pull down a long wire HF antenna and reset it up by Yakima. Found a magnetic variation map, lines make a hard right turn up there and then turn back roughly north. I was right in the middle of it.
Cussed a little, got back to work.
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