Travelling with a compass clinometer

Where possible, you should use a compass clinometer designed for the hemisphere that you are in, i.e. if you are in the northern hemisphere, your compass clinometer should have been made in/designed for the northern hemisphere.

A compass needle aligns to the magnetic field lines, which point into the earth at the north and south magnetic poles. In the northern hemisphere, the north end of the needle in a compass is pulled downwards towards the northern magnetic pole. However, if it is a northern hemisphere compass, a counterweight in the south end of the needle will balance the needle to compensate.

In the southern hemisphere, the south end of the needle in a compass is pulled down towards the southern magnetic pole. If a northern hemisphere compass was used here, the south end of the needle would already be heavier than the north end, meaning that the needle would not be properly balanced.

Some compass clinometers have been designed to be used in either the northern or southern hemisphere and this should be checked before using in the field.

There is also some thought that taking a compass clinometer on an aeroplane may potentially affect its accuracy due to X-ray scanners. Check with the manufacturer of your compass that flying will not affect your compass before travelling.