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10-28-2010 12:47 AM |
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Originally Posted by ≈Mortal•Mælstrom≈
(Post 641411)
I took courses on map reading and navigation in high school (ROTC) and I enjoy the fact that I am one of few (POSSIBLY) who could get practically anywhere with the right tools. One typical problem people need to be aware of when using maps and compasses are Magnetic North (MN) and True North (TN). Often this is what other students would mess up on when we had tests.
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You're thinking Grid North, not True North. But yes, It's a perishable skill, for sure. This is a big part of my job, so it's pretty important that I know it well. I've seen a lot of people remember there is a point to the declination diagram, but not be able to remember when you add or subtract the difference. I know in places like Alaska the difference is 30 degrees or more, so it's fundamental to remember.
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Most people use GPS but that only goes for so long, batteries die, connections get lost, technology fails. Crazy.
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A GPS is essentially a form of Intersection/Resection, where you find the coordinates to an unknown point by taking two or more known points (satellites instead of known land marks), shoot an azimuth from those points to the unknown (or from the unknown to the known points, in the case of Resection), and where they intersect on the map is unknown grid coordinate, which is relayed to you via the GPS. The same thing a protractor and compass do.
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