WHOLE CIRCLE BEARING AND REDUCED BEARING

In whole circle bearing (WCB) with respect to a meridian the bearing of a line at any point is measured. Its value varies from zero to 360°, increasing in clockwise direction. Zero is north direction, 180° is south, 90° is east, and 270° is west. In prismatic compass this type of bearing is used.

 Bearings are measured from north or south direction towards east or west in reduced bearing (RB) system. Therefore, angles are from 0 to 90° as shown in given figure. In Surveyor's compass this system of measuring bearings is used and it is also called as Quadrantal Bearing (QB). With letter N or S the bearing measured is designated in the beginning to shows whether it is from south or north. After the angle indicates whether the bearing read is towards east or west, the letter E or W written respectively.

From one system to the other system the conversion of the bearing can be easily carried out by drawing a sketch to indicate WCB or RB as shown in figure. It can be observed that conversion table is as given below: