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 its a tricky thing to remember, at least the way it has traditionally been taught, using an addition / subtraction method. Just when you think youve 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 earths 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 Hudsons 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 20east. This means that magnetic north is 20 east of true north. In Tennessee the angle of declination is 0, and in Maine, its 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. Thats 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 its available, its 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.
Thats 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
We went camping at Lake Lanier Georgia this fourth of July. Not sure if I will every go back. It was by far the worst experience I have had at a national park. But to be fair this is not the first time I have been to Lake Lanier and I enjoyed my other visits. Maybe it was bad because it was the fourth. Here is the good and the bad at Lake Lanier.
The Bad
1 As are all national parks it is supposed to be alcohol free. Besides listening to the rowdy people until way past midnight I found beer bottles along the lake shore and a half empty bottle of MD 20/20 in the childrens playground not more than a 100 yards from the entrance shack.
2 Did not see a single ranger after 9PM and believe they would have been very useful in keeping the noise under control. I understand the celebration of Independance Day and have no issue with that but does it have to be three days in a row.
3 I saw several people trying to fish along the banks early in the morning only to be ran off by a single boat whose occupants were too rude to find another spot.
4 The lake water level is very low. Sites that are supposed to be 20 ft. from the water are closer to 100 yds. This is not the parks fault as they are having a rather severe drought. With only a few boat ramps open people waited for hours to get their boats in and out of the water.
The Good
1 The grounds and facilities are well maintained.
2 Park rangers are very visible during the day.
3 Camp sites provide a very scenic veiw of the lake
4 If you own a boat there is still plenty of water to have fun in.
I haven’t posted anything for awhile and I apologize for that. I have been busy setting up another website CatfishAngling.com for my other outdoor love. This being Memorial Day weekend you can probably guess what I will be doing. I am going camping with my wife and three kids. I have always believed family camping brings a family closer together.
If you don’t already have a reservation somewhere or know someone on who’s land you can camp you are not camping this weekend. In fact if you are going to do anything on the Fourth of July weekend you had better plan it now if you haven’t already. Available camp sites are disappearing fast. I have already made my reservations for Lake Lanier, GA. I hope by the time I am going camping that the water level has returned to normal. That area has been in a drought for the past year and water levels have been way down.
This trip we are going to Lake Strom Thurmond, GA. I have never been there and hope it turns out alright. I have to go now as I have so much to do today before the kids get out of school. This is there last day and I want to leave as soon as they get home. I have to make sure everything on my checklist is packed and ready by then.
I hope you have as good a weekend as I am planning on having!
I just made my first camping reservation for the upcoming season. I am planning to spend Memorial Day weekend at Thurmond Lake, Georgia. I have never been there before so if you have any inside information I would love to here it. I choose this location primarily for it’s proximity to Savanah. I have never been there and the kids would love to see the beach and Ocean.
Enough about me. Those of us that do it all the time know that camping is a great way to enjoy the outdoors and take a much needed mini vacation without breaking the bank. A three day stay at the campground will cost you somewhere between $45 and $75. Compare that to $75 or more per day in a hotel.
If you are going to enjoy your trip you must be prepared. I always get all my equipment out of the garage and take inventory. I even go so far as to set up our two tents and let the kids sleep out in the backyard for the weekend. Nothing worse than arriving at your campsite only to find you don’t have stakes for your tent or one of the poles is missing. I will try and test everything I have all the while keeping a list of what I have and what I need. Two things I always need are batteries for either the lamps or flashlights and gas for my stoves.
If you are an experienced camper you probably already have a checklist tailored to what you need for a pleasant camping experience. A checklist is a must for every camper if you want to insure that the family has a good time. If you need one you can download a generic one here. You will need to tailor it to your particular experience.
