AZIMUTHS & BEARINGS

An azimuth is an angle measured clockwise from a meridian. The bearing of a line is the acute horizontal angle between the meridian and the line. A meridian is a reference line and may be the
direction of true north or true south, magnetic north or south, or any assumed line. The true (geodetic) north-south line is commonly used because it can be checked and re-established by observations on the sun and stars.

The following problems arise in connection with azimuths and bearings:
1. Conversion of azimuths to bearings, and vice versa.
2. Conversion of true bearings to magnetic bearings, and fice versa.
3. Conversion of a magnetic bearing at some past date to that for the present time, or vice versa,
the declination (angular difference between the lines to true north and magnetic north) being
different for the two dates.
4. Computation of the bearings of lines, given the actual or assumed bearing of one line and the
angles between successive lines.
5. Correction of magnetic bearings effected by local attraction.

All of these problems are readily solved by means of a simple sketch or sketches. Keeping in
mind these properties of azimuths and bearings will help avoid mistakes:

Azimuths Bearings
1) Values between 0° and 360° Values between 0° and 90°
2) Require numerical values only Require 2 letters and value
3) Can be true, magnetic, calculated, forward, back Same
4) Measured clockwise only Clockwise and counterclockwise
5) Measured from north only (or south only) in any survey Measured from north and south