Tuesday, December 5, 2017

You Don't Have to Wander or Be Lost

You've got a map and compass now. Great! Now you need to figure out how to make them do useful work instead of merely being neat trinkets.

North isn't exactly north. By that, I mean that there is "true north" which is the direction of the North Pole, and "magnetic north" which is close to the pole, but not quite there. North on your map refers to true north, and north on your compass is magnetic north. The difference between these two is called declination, and is used to make them work together.

Declination varies depending on where on the globe you are. It's about 11.5 degrees at my house, and can be even larger. Magnetic-declination.com will give you an accurate declination number for your home or trip destination. This article gives a good in-depth read on declination.

Now you need to orient your map and compass so that the north you're using on your map matches your compass. This is a very simple process, but describing it is very wordy. From compassdude.com:
  1. Lay your map out on a relatively flat, smooth surface. 
  2. Turn your declination-adjusted compass dial so due North is at the index pointer. 
  3. Place your compass on your map with the edge of the baseplate parallel to the north-south meridians on the map. Notice the orienteering lines and direction-of-travel arrow are all parallel with the map lines. 
  4. Turn the map and compass together until the compass needle is "boxed" in the orienting arrow (Red in the Shed). 
  5. Now, the map is oriented to the real world. If you know where you are on the map, you should be able to look in any direction and see the objects represented on the map in the same direction.

Now you know where you are, where you're going, and what direction gets you there. You can use the scale on the map to tell you how far away your landmarks and waypoints are, but how do you know how far you've gone or how close you are? If you know how long your stride is, you can simply count steps to get there. An easy way to track this is a device called ranger beads. These can be made fairly simply, but they're also cheap to buy.

The big key to ranger beads is knowing how many steps it takes you to go 100 meters. (100 yards also works fairly well.) Measure out a 100 meter distance and walk it several times, trying to keep an even, casual stride. Count the number of steps for each trip, and find the average step count for 100 meters. Then, as you're hiking, each time you reach that step count, advance your beads to track your traveled distance. A standard ranger bead set will count to 5km before it needs to be reset, which translates to a bit over 3 miles. 400 meters is 1/4 mile, 800 is 1/2 mile, and 1600 is a full mile.

If you can find a direction, and know the distance, you can get to anywhere you're going.


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