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Walks in Lancashire |
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Walks in Lancashire |
It is very easy to learn the basics of using a compass, it is much easier than mastering reading the map! Please remember that only in very exceptional circumstances (e.g. whilst crossing magnetic rocks, such as the Cullins on the Isle of Skye, or when you are very close to a metal object) is a compass wrong - trust it over your own judgement.
If you are following navigational points given to you, these are expressed as six figure grid references. The vertical lines on the grid of a map are the eastings, and the horizontal grid lines are the northings. For any quoted grid reference the eastings are always given first, being the first three numbers of the six figure sequence. The first two of the three digits are printed on the map itself, which give you the grid line you are to the right of, and the third digit is a measure of how far you are across towards the next grid line (whereby 0 is on the grid line whilst 9 is 9/10 of the way across to the next grid line).
e.g. 123456
The four stages involved in taking a bearing using a compass are set out below:
In order to find the bearing between two points, place the compass on the map with the edge of the base plate connecting the two points (the line you wish to follow).
Keep the compass still on the map, and turn the central housing of the compass, until the north-south housing lines on the compass are aligned with the north lines on the map.
Now turn the housing anti-clockwise by the magnetic variation shown on the legend on the map to compensate for the difference between magnetic and grid north. This magnetic variation changes with time and location - if you cannot see it use 5°. Magnetic north was estimated for the Yorkshire area at 5° west of grid north in 1998 and decreases by about 1/2° every 4 years.
Whilst holding the compass steady and level, turn yourself and the compass until the red north needle is aligned within the housing arrow. The arrow in the centre of the base plate of the compass now points in your direction of travel.
