Taking a bearing from the map. The SILVA 1-2-3 SYSTEM:

 

The easiest way to set a course towards the lake is with a simple and safe system used by expeditions, youth organisations, mountain guides, armies, orienteers and other navigators the world over: the Silva 1-2-3 System®

1. Place the compass on the map with the edge of the compass along the desired line of travel.

2. Rotate the compass housing until N on the dial points North on the map. Check that the compass housing red/black north/south lines are parallel with the maps meridians.

3. Hold the compass in your hand and turn yourself until the red end of the compass needle (North) points to the magnetic variation (somewhere between 18˚ - 25˚ for New Zealand depending on where you are*) on the adjustable dial. The front of the compass with the direction of travel arrow is now pointing towards your destination.

 

* Note: For general use a line can be marked on the dial between 20˚ (easily remembered and sufficiently accurate for most purposes) and the pivot to make it easier to keep the needle in the right position. On some of the Silva range you can set an adjustable indicator line to the variation.

 

 

 

 

Compass-speak:

Magnetic North vs. True North

A compass points towards magnetic north, but this is not the same as true north. Sound confusing? Magnetic north is the direction the needle of the compass points to. This direction is based on the magnetic fields of the earth and is not the same as true north, which is the geographic north or toward the North Pole. In New Zealand magnetic north is actually around 23º east of true north (varies from one end of the country to the other). This is known as magnetic declination.

 

Global Magnetic Regions:

Because of the Earth’s curvature and variances in the Earth’s magnetic field, a compass designed for the northern hemisphere will ‘stick’ in the southern hemisphere, as it will basically be trying to point towards the ground.

 

Magnetic ZonesThe image to the left shows the 3 magnetic zones Silva use when producing compasses. Depending where in the world you are any standard compass you purchase should have its needle balanced only for that region. e.g: most compasses sold in New Zealand will only be most effective in New Zealand and Australia.