Before you can navigate with a compass you must be familiar with its design. The picture below shows the popular Silva Expedition 4 compass and all its important features, many brands and styles exist but most will have the illustrated features present.
This is what the compass and its housing are attached too. The base plate has a number of markings that are explained below
The compass housing contains the compass needle and fluid, the edge of the compass housing has all the 360 degrees of a circle printed, is used for showing your bearing and rotates.
These lines are used to line the compass with the easting lines of a map, this will help you keep the compass housing pointing north
The compass needle is the most critical part of the compass. The red end has a N printed for north and will point north when held flat.
BEWARE – Metal objects and electronic signals can effect the compass needle so ensure you keep it away. Certain devices can reverse the polarity of a compass so ensure you store it away from any of the above objects.
This is found within the compass housing, when you take a compass bearing you will need to align this arrow with the compass needle to aim on your bearing
Direction of Travel Arrow
When taking a bearing this arrow will be used to point the direction you wish to travel. Some compasses will have a long black line printed on the base plate that can be used too.
This is the line where you will find your bearing, some compasses its a black line others its an arrow.
These scales can also be called romer scales and are used for measuring distance and grid reference. On the Silva Expedition 4 you will find the three most popular scales that are used. 1:25 1:40 and 1:50
Thanks for reading, this blog was developed as part of National Map Reading week.
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