Sometimes a task or survival skill, when viewed in its entirety, seems to be overwhelming (Such as where do you start to learn land navigation?) The best way tackle learning such a skill is to break things down into smaller “baby steps.”
Land navigation expert Blake Miller explains how to make sense out of true north on s topographical map.
By Blake Miller
Keeping navigation simple is my goal. Backcountry navigators have the option to set their compass to work in degrees magnetic (in relation to magnetic north) or degrees true (in relation to the North Pole.) I find that working in degrees true is simple and straight forward.
I spent many long hours on the bridge of destroyers while serving at sea in the Navy. At the start of a bridge watch I carefully checked the navigation picture with a solid review of the chart (a mariners map), the compass, celestial observations reported and electronic navigation systems.
Compass and directional data presented to me was in degrees true.
It was natural then, to apply degrees true to my backcountry navigation. It’s just so simple.
A hiker’s magnetic compass provides direction in terms of degrees measured from the earth’s magnetic north pole. The red magnetic needles swings and points to magnetic north.
Declination must be accounted for with any magnetic compass. Declination is the distortion of the earth’s magnetic field caused by the movement of molten metals deep inside the earth. (For more information, read my post on declination HERE.)
When working with map and compass the angular measurement of declination will either be added or subtracted to arrive at a true bearing. Calculation is necessary because a topographic map is oriented to degrees true; compass and map must match.
I found this process to be cumbersome.
Long ago I swapped out my basic compass for one that can be adjusted for declination. The compass needle still points to magnetic north but the dial on the rotating compass housing provides data in degrees true; it has been adjusted. I can pre-set the declination adjustment at home before starting my trip. I can find the declination information at the bottom of my USGS map, or, if the map is old, I’ll visit www.magnetic-declination.com to get the current value.
Now my compass is matched to the map.
The next step is to align the Global Positioning receiver (GPS) to match the map and compass. I’ll due this via the “set up” menu.
Now all my navigation equipment matches.
Blake Miller has made a career out of staying found and knowing where he is at all times. His formal navigation training began when he joined the U.S. Navy in 1973. He served as an officer aboard several Navy ships over his
twenty-year career; many of those tours included the duty of Navigator. Blake began working with satellite navigation systems at sea in 1976, culminating with the then-new satellite positioning systems aboard the Battleship WISCONSIN in early 1990.
In 1998 Blake started Outdoor Quest, a business dedicated to backcountry navigation and wilderness survival. Blake has taught classes to wild land firefighters, state agency staffs, Search and Rescue team members, hunters, hikers, skiers, fishermen and equestrians. He regularly teaches classes through the Community Education programs at Central Oregon (Bend) and Chemeketa (Salem, OR) Community Colleges.
As a volunteer, Blake teaches navigation and survival classes to students in the local school districts, and conservation groups. He is a member of a Search and Rescue team.
To hear the Blake Miller interview about choosing a magnetic compass and GPS on SurvivalCommonSense.com Radio, click here.