True North & Magnetic Declination - A Trick to Make it Stick

Magnetic declination is an essential principle to understand when navigating your way through the wilds with map and compass.

Yet it's a tricky thing to remember, at least the way it has traditionally been taught, using an addition / subtraction method. Just when you think you've grasped it, the concept floats away, like fog in the morning light.

Well there is a simple, practical approach to adjusting for magnetic declination when finding your bearings. The whole explanation begins with a definition of 'north."

There are 2 Norths

A lot of people know that there are 2 norths in terms of maps and compasses. A map shows true north, or the Geographic North Pole where all lines of longitude meet. The earth rotates around an imaginary axis that runs through the North and South Poles.

A compass needle points to magnetic north, which is determined by the earth's magnetic field. The location of magnetic north moves over time, at about 5 miles per hour. Right now it is slowly creeping around somewhere NW of Hudson's Bay in Canada, about 450 miles away from true north.

Magnetic Declination

The angular difference between true north and magnetic north is known as "declination," or "variation" in the aviation world. Declination is different for different parts of the globe. In Washington State, the angle of declination is 20°east. This means that magnetic north is 20° east of true north. In Tennessee the angle of declination is 0°, and in Maine, it's 20° west.

Declination values can be found in the margins or legend on topographic maps. Because the point of magnetic north is constantly moving, it is important to have a recent topo map for finding your way in the woods.

A similar point to remember is that compasses are calibrated for different parts of the world. So when you purchase a compass, be sure that it is intended to be used in the area of your big hiking vacations.

How to Find Your Bearing

Follow these steps to find your bearing:

1. Place the compass on the map with the arrow on the base plate pointing in the direction you want to go.

2. Turn the dial face of the compass so that north on the compass is parallel with north on the map.

3. Place your compass level in the palm of your hand and turn yourself until the needle in the compass aligns with the North marking on the face dial.

4. The big arrow on the base plate is now aligned with your bearing.

Declination Value and Bearings - A Trick to Make it Stick

If you walked 10 miles through the woods in Washington State, without factoring declination value in your bearings, you would finish over 3 miles off target. That's too much!

To avoid confusion in finding bearings, keep the central principle in mind:

Make map bearing = magnetic bearing.

You will achieve this in the field by adjusting your bearings to compensate for magnetic declination. There are 2 ways to account for magnetic declination in finding your bearings: an adjustable compass and marking your non-adjustable compass.

The easiest way is with an adjustable compass. Simply turn the declination adjustment screw on the compass to the correct value and all readings are automatically converted to true north. If it's available, it's always best to have an adjustable compass on your walk.

The next best way to account for declination is to mark the declination value on your non-adjustable compass at the beginning of your journey.

That's simple to do. For example, when the map indicates a declination value of 20° west, you will mark your compass dial at 340°. If the map indicates a declination value of 10° east, you will mark your compass at 10°. Make the mark with a permanent marker and erase later with rubbing alcohol.

Now when you take your bearings in the field, place your compass level in the palm of your hand and turn yourself until the needle in the compass aligns with the declination marking on the face dial. Then the big arrow on the base plate will point toward your bearing and automatically compensate for magnetic declination.

Outdoors Adventurer, Writer and Webmaster Will Robertson lives with his family in Little Rock, Arkansas.

Explore the best hiking vacations and gear on the planet at: http://www.hiking-vacations-and-gear.com

In The News:

The Best Reasons to Get Outdoors  Architectural Digest
Outdoors: Alright, Fair Enough!  Dodge City Daily Globe
A bite of the outdoors  The New Indian Express
Dan D. Outdoors  Geneseo Republic

A Retired, Single RVer Travels

For some 30 years I practiced law in Mesa, Arizona.... Read More

Backcountry Safety ? An Essential 10-Point Checklist

The call of the wild can be seductive. The exquisite... Read More

Canoe Trip with Nature

A canoe trip is a great way to appreciate Nature!A... Read More

How To Buy a Used RV - Part 2

The key to getting a good bargin, instead of a... Read More

A Holiday in Rajasthan

Romancing History ? A Holiday in RajasthanRajasthan, the name evokes... Read More

Take a Hiking Pole on Your Next Hike

It is the downhill ski racing competition of the winter... Read More

Unforgettable Cape Cod Vacations: The National Seashore Gift

Take a captivating trip through the Cape Cod National Seashore... Read More

Your Virgin Bushwalk

Isn't it time you stepped out of the concrete jungle... Read More

Tent and Outdoor Gear Care and Repair

TENT CAREYou should seal all floor seams and those seams... Read More

Adventure Travel on Horseback

When you think of "adventure travel," what crosses your mind?... Read More

African Safari Gear Packing List - What To Take Along

The last thing you want on an African safari is... Read More

Disneyland for Hikers: A Walk to Mt. Whitney

Base camp sits at 12,000 feet - stark, windy, unshaded... Read More

True North & Magnetic Declination - A Trick to Make it Stick

Magnetic declination is an essential principle to understand when navigating... Read More

Costa Rica White Water Rafting Trip

Costa Rica's mountainous topography and copious rainfall are both responsible... Read More

Catch Another Falling Star

Recently we stayed at a state campground in Michigan near... Read More

Shark Pictures Not The Real Thing

Pictures of a massive dead Great White shark on the... Read More

Backpacking Journals ? Preserve Your Backpacking Experiences

Backpacking is a great way to escape the rat race... Read More

Hiking Shoes Versus Hiking Boots

Hiking shoes versus hiking boots? Hiking shoes win. Okay, next... Read More

Why Should You Use Hiking Poles?

Why should you use hiking poles is perhaps the first... Read More

Side-Tripping in Montana

Nightlife in Big Sky, Montana is more exciting than you... Read More

Hawaii Snorkeling - An Underwater Paradise

Hawaii snorkeling is a fun activity available to almost any... Read More

RV Camping at Casinos

There's nothing that will quicken the interest of RVers like... Read More

Sleeping Pads For Ultralight Backpackers

Ultralight backpackers want to give up weight, not comfort. Sleeping... Read More

Lake Jipe straddling Tanzania and Kenya

So unknown is this treasure of Lake Jipe not many... Read More

Penguin Parade

Phillip Island is a small island and nature reserve off... Read More