Map Compass Land Navigation

How to properly navigate with a map and compass.

Getting lost in the wilderness can be a scary thing.  Most of us do not spend a great deal of time outdoors, so we don't realize how difficult it may be to find our way home once we venture past the sound and lights of the city.  I saw a study on North American Bees a few years ago, where the scientist took a bee from it's hive, put it in a box, put the box inside a van, and drove a mile from the hive in sporatic directions and once released, the bee flew in a straight line back to it's home.  Obviously, the bee has some sort of higher programming than humans, or they have very tiny maps and compasses.  With proper training, humans can have nearly equal proficiency in getting where we want to go.

First, buy a lensatic compass from an Army/Navy surplus store and find a map of your location.  The map needs to have some sort of measurements for lattitude and longitude, and an indication of terrain features.  If you can find a map made by DMA (Defense Mapping Agency) you are in luck.  They use a grid system which will put you to within one square meter of what you are trying to find, and they have graduated lines to show you terrain height and slope.  The ten digit grid system is what the U.S. Marine Corps uses.  As for latt/long, the numbers you will find describe Degrees, minutes, then seconds respectively.  Lines of lattitude are horizontal, like the rungs of a ladder.  Lines of longitude go north and south.

Now you have your basic tools.  Assume you get kidnapped and dropped off in a wooded area far from civilization.  Your kidnappers gave you a contour map and compass, and were also kind enough to laminate your map and give you some grease pencils and alcohol wipes.  They are nice kidnappers. On your map, find your location.  You need to become proficient at 'terrain association', in which you try to recognize prominent terrain features.  Locate two seperate features that you can identify by sight and on the map.  Shoot an azimuth (aim your compass at each feature and take note of the degree to it, and 180 degrees from it).  Try to find two features that will create a greater than 30 degree angle to increase the accuracy of yourmeasurements.  Draw that angle on your map with a grease pen and do the same for the second feature.  Where the lines converge is your location, if you were right about the terrain features, of course.  This is where dead reconing comes into play; if you recon wrong, you're dead. 

Next step is to determine where you would like to go.  Before you start walking there are a few more things to consider, like the three types of North.  Yeah, there are three of them: Magnetic, Grid, True.  Magnetic North is where your compass is pointing, which changes every year.  A magnetic compass will point to wherever the greatest magnetic field is, which on planet earth is somewhere around the Hudson Bay in Canada due to the large iron ore deposits therein.  So if you were in Iceland, your compass would indicate that North is Actually West.  Don't worry, your map should have something called a 'declination diagram' at the bottom, which will tell you how many degrees you have to adjust to find Grid North at the time.  Remember, Magnetic North changes due to the shifting of the tectonic plates.  Grid north is simply the top of your map.  This gets a little tricky because the earth is round so you can't perfectly translate that into a square shape.  While lines of lattitude are exactly parrallel, lines of longitude converge at the north and south poles so they should not be parrallel on a map, but they are.  The declination diagram takes this into account as well.  True north is the simplest of the three; it is the axis on which the earth rotates and it matters little to the navigator.

Now you know where you want to go, so mark it on the map and shoot an azimuth.  The most basic way to get there is to follow the line on the map.  Orient your map on the ground so that the top of the map is north, and set your compass down on your line.  See what the angle says then subtract or add what the declination diagram says, and follow that azimuth until you reach your destination.  That is easier said than done, as terrain goes up and down, becomes treacherous and sometimes impassible.  Unless you are in a desert, but that is not the better situation because it is unlikely you will be able to find your starting location unless you are proficient at celestial navigation.  So, take a look at your map and try to determine what route you could easily walk and try to break that down into 'legs' (or checkpoints, if you're in the military).  The most proficient navigator doesn't need the compass for every step, but simply does a 'terrain countdown' from point A to point B.  That means you check the map and determine what prominent features you will pass and count them down: mountain peak to the north in 250 meters, depression in 500 meters, river flowing east-west in 230 meters, destination 300 meters beyond that, etc. 

Now let's assume your compass breaks, or you met another navigator along your journey and you traded it for a pack of ho-ho's.  Your fail-safe is to wait for nightfall and locate the constellations Orion, and the Big Dipper.  Look at the part of the big dipper where water would pour out, if you tip it.  Draw an imaginary line upward, about five heights of the bowl of the dipper.  There you will find Polaris, the North Star.  To verify, draw another imaginary line from Orion's belt, this will intersect with your original line from the big dipper, if you're correct.  You can use that to move in a cardinal direction and hope to hit something else you can associate with, like a road, stream or rental car station.

Like anything else, land navigation takes practice.  You can start by navigating a park or a wooded area that you know fairly well, and if possible, be sure to take with you a cell phone, spare batteries and a survival kit, just in case.  Have fun and be safe.


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