The compass is a simple magnetic tool that can assist
you in doing the following:
- Determining the direction in which to travel from where
you are to some distant point (physically visible or noted
on a map)
- Determining approximately where you are based on bearings
to multiple identifiable points on a map
The Simple Compass Parts:
How it works
In simple terms, the needle floats in a clear liquid and,
assuming not interfered with by other metal or potentially
magnetic objects, will continue to point towards "Magnetic
North".
Knowing that the needle is pointing a specific direction,
our desired direction of travel can be measured relative
to this needle. The most common method of expressing a direction
is by using an azimuth or "bearing". An azimuth
is defined as a horizontal angle, measured clockwise from
north in units of degrees (0 degrees to 360 degrees).
Caveats worth mentioning:
- A compass being used next to your SAR radio, or next
to a flashlight, or near almost ANY metal object WILL
CHANGE YOUR READING — be careful when taking a bearing
- As we learn the compass we learn terms such as "Magnetic
North" and "True North". As a rule in Sonoma
SAR, ALL bearings are magnetic when in the field. The
only time we talk about "True North" is in reference
to a map and we will demonstrate how we eliminate the confusion
of "declination". More on this later.
Using
The Compass
Triangulation
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