In whole circle bearing (WCB) the bearing of a line at any point is measured with respect to a meridian. Its value varies from zero to 360Â°, increasing in clockwise direction. Zero is north direction, 90Â° is east, Â 180Â° is south and 270Â° is west (Ref. Fig. 13.2). This type of bearing is used in prismatic compass.
In reduced bearing (RB) system, bearings are measured from north or south direction towardsÂ east or west. Hence, angles are from 0 to 90Â° as shown in Fig. 13.3. This system of measuring bearingsÂ is used in Surveyorâs compass and it is also known as Quadrantal Bearing (QB). The bearing measuredÂ is designated with letter N or S in the beginning to indicate whether it is from north or south. The letterÂ E or W written after the angle indicates whether the bearing read is towards east or west, respectively.
The conversion of the bearing from one system to the other system can be easily carried out byÂ drawing a sketch to indicate WCB or RB as shown in Fig. 13.4. It may be observed that conversion tableÂ is as given below: