What is the Whole Bearing System (WBS)?
The Whole Bearing System (WBS) is a notation of bearings used in compass surveying. It is based on angles measured clockwise from the north direction, ranging from 0° to 360°. It is also referred to as the absolute bearing system.
What is the Quadrantal Bearing System (QBS)?
The Quadrantal Bearing System (QBS) is another notation of bearings used in compass surveying. It is based on angles measured clockwise from the east, north, west, and south directions. It is also referred to as the relative bearing system, as it expresses the direction of one point with respect to another.
How to Convert WBS to QBS and Vice Versa
The WBS and QBS systems can be converted to each other by a simple calculation. To convert from WBS to QBS, the angle is divided into four equal parts and the direction is taken into consideration. For example, if the angle is 315°, it can be divided into four parts of 90° each, and then the direction would be NW (northwest). To convert from QBS to WBS, the angle is simply added to the cardinal direction.
Bearing and Angles
What Is a Survey Line?
A survey line is a line measured in relation to another survey line or with relation to the meridian. The first method gives the angle between the line, while the second gives the bearing, which is the direction of the line with respect to a given meridian.
Types of Meridian
There are three main types of meridian: true, magnetic and arbitrary. A true meridian is the line of longitude that passes through the point of observation, a magnetic meridian is defined by the direction of the magnetic field, and an arbitrary meridian is any line of longitude chosen for a specific purpose.
1. True Meridian
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The True Meridian: A Line That Passes Through a Point
The true meridian is a line that passes through a point, with a plane passing through the point and the North-south poles. It forms the line that passes through the true north and south poles.
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The True Bearing of a Given Line
The true bearing of a given line is the horizontal angle made with the true meridian through one of the extremities of the line. It is calculated by measuring the angle formed between the true meridian and the given line.
2. Magnetic Meridian
What is the Direction of a Freely Suspended Magnetic Needle?
The direction of a freely suspended and balanced magnetic needle is known as the magnetic meridian. This direction can be determined by using a magnetic compass, which must be free from any other attractive forces.
What is the Magnetic Bearing of a Given Line?
The magnetic bearing of a given line is the horizontal angle formed between the magnetic meridian passing through one of the extremities of the line and the direction of the magnetic needle. This angle can be used to calculate the bearing of the line in relation to the magnetic meridian.
3. Arbitrary Meridian
Arbitrary Meridian
In certain situations, a convenient direction is established with respect to a permanent or a common mark or a signal in the area, during the survey. These are called arbitrary meridians, which helps to determine the relative positions of the survey line.
Arbitrary Bearing
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
Whole Circle Bearing System
The Whole Circle Bearing System, or Azimuthal System, is a system used for surveying and navigation. It is based on a 360-degree system, where angles are measured in degrees from 0° to 360°. The system is used to determine the direction of a line from the observer to a point relative to the north direction.
Quadrantal Bearing System
The Quadrantal Bearing System, also known as the Reduced Bearing System, is a system used for surveying and navigation. It is based on a 90-degree system, where angles are measured in degrees from 0° to 90°. This system is used to determine the direction of a line from the observer to a point relative to the north direction.
1. Whole Circle Bearing System or Azimuthal System (W.C.B)
What is Bearing?
Bearing is the angle between two lines and is measured in degrees. It is used to measure the direction and orientation of one point relative to another. The bearing value ranges from 0 degrees to 360 degrees.
What is a Prismatic Compass?
A prismatic compass is an instrument used to measure directions. It is graduated with a WCB system, which stands for Whole Circle Bearing.
What is WCB System?
The WCB system is a system of bearings used in a prismatic compass. It is composed of four parts: Q1, Q2, Q3 and Q4. These bearings are used to measure the direction and orientation of one point relative to another.
2. The Quadrantal Bearing or Reduced Bearing System (QB)
What is the QB System?
The QB system is used for measuring the bearing angle of a line. The bearing angle is measured either from North or South, depending on which is closer. The direction of the measurement (clockwise or counter-clockwise) is determined by the quadrant in which the line lies.
How is the Bearing of a Line Represented?
The bearing of a line is represented by “QB” (Quadrant Bearing). For example, if the bearing of a line is from the South and lies in the South-East quadrant, it is represented as S B E (South Bearing East). The QB lines range from 0 to 90 degrees.
What is the Range of QB Lines?
QB lines range from 0 to 90 degrees.
