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Navigation with compasses and other aids

Most people recommend learning to navigate with the map alone before using a compass as well.
This will encourage making maximum use of the information on the map.

Good map reading and the ability to match features on the ground with those on the map are the basis of accurate navigation.
Compasses can be used to help but should not normally be relied upon.
GPS units must never be relied upon for navigation – they should be a back up for map and compass.
Altimeters can also aid navigation in hilly terrain.
The most important navigational aid is the one between your ears and this needs frequent practice to keep it working well!

Use these links for additional information:

"Anatomy" - components of a compass

The type of compass most commonly used by walkers is the base plate compass, such as the one shown below.

There are other types such as sighting compasses, button compasses, and digital compasses. A sighting compass is bigger, more expensive and more accurate. It is probably better to become proficient at using a base plate compass before considering using a sighting compass. Button compasses are small and less accurate - they can be useful if you just want confirmation that you are heading in the right sort of direction rather than needing to follow accurately a bearing. I tend to clip one onto the cuff of my sleeve if I am using one so it is always accessible. As with everything else digital, never rely on a digital compass whether it is in your watch, GPS or smart phone - if your battery dies so might you.

When buying a compass consider the following:
  1. Is it manufactured for uses in the part of the world where you plan to use it? (some are designed for us in only the southern or northern hemisphere)
  2. Is the base plate long enough? If it is short it will be hard to use the compass for taking bearings off a map.
  3. Does it have one or more romers and are these calibrated for use with the maps scales you plan to use? (a romer designed for use with a "metric" map will be little use with an "imperial" one)
  4. Is there a small magnifier built into the base plate? This becomes more important after the age of 45 when near vision deteriorates & the magnifier may reduce the need to fish reading glasses out of the pocket where they are stowed.
  5. Does it use degrees rather than mils? Civilians use degrees.
My personal preference (for use in the UK) is a Silva Expedition 4 base plate compass (there are links to it in the "buy recommended books" link on the left).

compass.jpg

features of a compass (video)

"Physiology" - uses of a compass

Compasses can be used in several ways to help navigation
The most important, most commonly used feature is its ability to indicate where north is.

Magnetic needle

Set the map
Indicate the direction of travel for the next leg (e.g. when at a path junction)
Move in a known direction in featureless terrain/in poor visbility

Compass housing

Take bearing from the ground
Take bearing from the map

Romer

Determine a grid reference on the map
Measure distances (if you use the same romer scale as you use for grid references then (assuming 1 km grid, as in the UK) each number from 0 to 9 represents 100m on the ground)

videos on using map and compass together