Navigation is one of the most basic outdoor skills that we all must learn. Everyone who considers spending a lot of time off the beaten track MUST be familiar with the basic use of map and compass. In this regard there is no substitute for practise, and you don't have to be in the "boonies" to practise these skills either, take sightings the next time you go for a walk, triangulate your postion on the way to work, become entirely familiar with your compass and ensure that the "trap" of magnetic declination will never catch you!

In recent years the decreasing price and increasing availability of portable Global Positioning Equipment has led many to believe that the magnetic compass has had it's day, but consider this; a compass needs no batteries, it does not depend on getting a good "fix" and nobody can switch off a compass at whim. And what if even a compass is not available? You can manufacture expedients and the sun and stars are always there for you...You just need to know how to use them.

READING A MAP It is obviously not possible to reproduce height on a flat sheet of paper, so maps measure terrain by use of lines, known as contours, at regular intervals - usually every 50 ft. These lines join points at the same height and usually form some sort of irregular shape, if a line ends abruptly it represents a sharp change of altitude, a cliff for example.

Remember that although it is possible to make a good estimate of what terrain lies between contours, you cannot be sure, there could for example be deep hollows or sharp outcrops or many other variations in the 50 ft between contours.

MEASURING DISTANCE The countour lines it must be borne in mind represent altitude only, they do not show the actual distance to be travelled to climb a slope, they show relative position and are not to fixed scale as is the horizontal plotting on the map. Before you can use a map you must know and understand it's scale, this is usually shown as a bar in the map margin and a a ratio, a common one is 1:50,000 which means that every measure on the map represents 50,000 such units on the ground.

KEY You should also be familiar with the map "Key" which is the guide to the symbols used on the map to represent differing terrains and features. Once you have mastered a map's key you can learn a great deal about your surroundings.

THE GRID Maps carry a grid of lines which divides them into individual squares. This grid will either be based on lines of latitude & longitude or a special national grid developed by the local mapping authority, in addition military maps may use a letter based system known as "Georef". These squares can be used to describe your position by using a coordinate made up from the line references from two adjoining sides of the map. This will lead you to a particular square and further visual subdivision into further tenths will will pinpoint you position almost exactly. A further use of these lines is as a rough "ready reckoner" for measuring distance. e.g on a UK OS map the lines are 1km apart and the distance across the diagonal is 1.5km.

"NORTH"Unless marked with lines of longitude, the grid lines on a map are not an indication of north & south altough they may be close to it. Remember also that your compass points not to true north but to magnetic north, the relative position of which varies depending on where you are in the world and with time, magnetic north moves! To take accurate bearings you will need to know the variation between grid, magnetic and true north. Most maps indicate the deviation of magnetic north, but if not you can obtain it by using the Pole star.

LOCAL MAGNETIC VARIATIONTo ascertain your local magnetic variation, point the north mark on your compass at the North Star. Record the difference between the pointer and true north. Then by lining up the compass with the grid lines on the map you can discover your local varation.

EXPEDIENT DIRECTION FINDING

The Earth's relationship to other bodies in the universe has been used to plot direction for thousands of years, ask any sailor! Everyone knows that the sun rises in the east and sets in the west, (but not exactly east or west), in the Northen hemisphere the sun at it's highest point in the sky is due South.

USING THE SUN find a patch of flat, unbroken ground, place a stick about 3ft long as upright as possible on it and mark where the tip of the shadow falls, using a pebble. Wait at least 15 minutes and then mark the new position of the shadow's tip, aline joining these two points runs east-west the first pebble being the west.

USING THE MOON The moon has no light of it's own, it reflects the sun's light. It orbits the earth in 28 day cycles when it is on the same side of the earth as the sun, no light is visible, a "new moon"- then it reflects light from it's apparent right hand side as it "waxes it reflects more and more light until it becomes apparently "full" when it is on the exact opposite side of the earth from the sun. Then it wanes again becoming less and less until it reduces to a tiny sliver of light on it's "left" hand side. This can be used to find direction. If the moon rises before the sun has set the illuminated side will be on the west, if the moon rises after midnight the illuminated side is in the east. Thus providing a rough reference.

USING THE STARS To use the stars to ascertain direction it is necessary to learn a few constellations (a) The Plough, or Big Dipper, (b) Cassiopeia, (c) Orion. all of which appear to circle the North Star (d). Each can be used seperately to reference the Pole Star which is always to the north in the northern hemisphere. Study their positions in relation the Pole Star so that you will always be able to find it.

IMPROVISING A COMPASS A compass can be improvised from any piece of very light ferrous metal, a pin, a razor blade or length of wire. To use it as a compass it must be magnetised, there are several ways to achieve this by stropping carefully against your hand, by rubbing against a piece of silk, by stropping in one direction only with another magnetised item or by coiling insulated wire around it and connecting a battery for 5 minutes or so. Suspend your pin/razor whatever fron a piece of string, and one end will always point toward magnetic north. You will have to ascertain which end points north by other, less accurate means. Be sure and mark it!. You can also try floating a pin on top of calm water, this is a more reliable method, but can be tricky to achieve.

USING YOUR WATCH If you have a standard two handed watch, you can use it in conjunction with the sun to tell direction. The watch must be set to local REAL time, i.e not daylight saving time, summer time etc. In the Northern Hemisphere: hold the watch horizontal. Point the hour hand at the sun. Bisect the angle between the hour hand and the 12 mark to give a north-south line.

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