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The whole bearing system (WBS) and the quadrantal bearing system (QBS) are two bearings systems used in the compass survey. With a simple calculation, the WCB system can be converted to QBS.
The article briefly explains the different bearings used in the survey and classification of bearings (WCB and QB system).
The article briefly explains the different bearings used in the survey and classification of bearings (WCB and QB system).
Bearing and Angles:
You may measure a survey line in relation to another survey line or in relation to the meridian. The first method provides the line angle. The second one is giving the bearing The bearing can, therefore, be defined as the line's direction for the given meridian.
There are mainly three types of meridian:
- True meridian
- Magnetic meridian
- Arbitrary meridian
1. True Meridian:
A line passes through a point, with a plane passing through the point and the north-south poles forming the true meridian.
In other words, it forms the line that passes through the true north and the south poles.
The true bearing of a given line is the horizontal angle made with the true meridian through one of the extremities of the line.
2. Magnetic Meridian
The magnetic meridian is the direction shown by a freely suspended and floating balanced magnetic needle. To determine the magnetic meridian, a magnetic compass can be used. For this purpose, the magnetic compass used must be free of other attractive forces.
The magnetic bearing of a given line is the horizontal angle that it makes with the magnetic meridian that is passing through one of the extremities of the line.
3. Arbitrary Meridian
In some situations during the survey, a convenient direction is set for a permanent or common mark or signal in the area. These are called arbitrary meridians which help determine the survey line's relative positions.
The horizontal angle made by a line with the arbitrary meridian passing through one of its extremities is called as an arbitrary bearing.
Whole Bearing and Quadrantal Bearing Systems:
A WCB bearing system measures an angle in the clockwise direction from the magnetic north or to the south.
hence, the bearing value varies between 0 degrees and 360 degrees. A WCB system graduates from a prismatic compass.
The Quadrantal Bearing or Reduced Bearing System (QB):
The bearing angle is measured in the QB system either from the north or from the south, whichever is nearer. In either clockwise or anti-clockwise, this can be measured Here it is necessary to mention the quadrant at which the line lies. The Q.B lines vary from 0 to 90 degrees.
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