How To Read A Compass

Does looking at a compass leave you lost and confused? Read our quick guide and get yourself back on track!

Most of navigation is map reading - relating features shown in symbol form on paper to what you physically see in front of you. The compass is simply a reference which points in a given direction. Despite what you may think, it’s still incredibly handy to know how to use.

Read on for our handy guide on how to decipher a compass, and once you’re done, why not develop your knack for map reading?

Compass Principles and Features

Bearings

Compasses are basically designed to show you where north is situated in time and space. Knowing the location of north allows you to identify all of the other directions (south, east and west) in what is known as the ‘compass rose’, as you travel.

Many compasses take this one step further, by allowing you to assign a specific numerical direction, called a ‘bearing’ to any direction in the full 360 degree circle around you.

This means you can head toward a very specific destination, rather than simply heading in a general direction such as southwest.

To convert general compass directions into bearings, a compass has a special rotating bezel mounted around the outside edge of the compass needle. This bezel, which is divided into 360° usually in 2° to 5° increments°, measures the direction towards a given object in terms of an angle; specifically, the clockwise angle between a straight line pointing due north and a straight line pointing toward the object. This bezel allows you to express any specific direction as a number between 0 and 360.

The importance of bearings

Following a bearing that is just one degree off can translate into a 25 metre variance over a kilometre. This means that after a 10 kilometre walk, you may miss your target by over 200 metres. In the bush, a few metres can mean the difference between spotting a track or creek and missing it completely.

Triangulation

Triangulation is one of the most common and most useful navigation techniques that employ both a map and a compass. It is a simple procedure that, when done correctly, can pinpoint your exact position on your map, even if you have no idea where you are.

It involves taking a look around and trying to identify two unmistakable landmarks, like two mountain peaks. If you take two accurate bearings on the two peaks, and draw a line on your map from each landmark along the bearings taken, your location will be where the two lines intersect. Triangulation is based on the principle that once you've taken a bearing on a visible landmark, you can logically assume that your position lies somewhere along a line drawn to that landmark along that bearing; the second bearing allows you to define the point.

Magnetic Declination

Map and compass navigation works on the principle that you know one thing at all times—the whereabouts of north. To find it, simply look at where the red end of your compass needle points.

The problem is that navigation is based on knowing where ‘true north’ is—the location of the North Pole. And unfortunately, that's not where compass needles really point. Compass needles actually point toward ‘magnetic north’, a point that is close to true north, but not exactly. And this is where ‘declination’ comes in.

Declination is the angular difference between ‘true’ and ‘magnetic’ north. The tricky thing about declination is that this angle is different depending upon where you are standing in the world.

Declination is usually indicated diagrammatically with a series of arrows drawn on a map. These diagrams are often not to scale, so always use the values not the drawing, to set your compass.

People navigate successfully with maps and compasses by taking the declination angle into account when they make their navigation calculations (basically, by adding or subtracting the angle of declination from the compass bearing numbers that they read off their compasses). Some compasses can be set so that they remain adjusted for an entire trip.

Please not that this is simply an introduction to some of the basics of compass use and functionality. We recommend that before you set out anywhere relying on your ability to navigate that you ensure you are supremely confident in how to use your preferred navigation device, and that the device has been tested and proven to be in good working order.

While compass reading abilities are very useful, sometimes you need technology to work you out of a tight spot and Wild Earth is the perfect place to purchase some of the best handheld gps navigators in Australia! Visit our website and check out our range of superior quality handheld gps units to avoid having to pull a Bear Grylls when your compass decides not to cooperate!