Difference Between Whole Circle Bearing and Quadrantal Bearing | What Is WCB | What Is QB

Introduction of WCB Vs. QB

When discussing wcb in surveying, it’s essential to understand that Whole circle bearing(WCB) and Quadrantal bearing(QB) are the two types of bearing used in the field of surveying for the purpose of measurement of the bearings.

In this article, you will get to know about the whole circle bearing and Quadrantal bearing and their differences.

What Is Whole Circle Bearing (WCB)

• For those wondering ‘define whole circle bearing‘, the whole circle bearing (WCB) is defined as the bearing of the line at any point which is measured with respect to the Meridian.
• The Whole Circle bearings values range from 0° to 360°.
• The Whole circle bearing is generally used in the Prismatic compass.
• The whole circle bearing is used to measure the angle in the clockwise direction from the magnetic North.
• The Prismatic compass is graduated by Whole circle bearing.

Also, read: What Is Passometer & Pedometer | Advantage of Passometer & Pedometer

Example of Whole Circle Bearing (WCB)

• If the survey line falls between the first quadrant then the  Whole Circle Bearing lies between the 0° to 90°.
• If it lies between the second quadrant then the Whole Circle Bearing of that survey line lies between 90° to 180°. If it lies in the third quadrant then the Whole circle bearing will be between the 180° to 270°.
• And in the fourth quadrant, the Whole Circle Bearing values range between 270° to 360°.
• The Whole circle bearing of any line can exceed up to 90°. When converting whole circle bearing to reduced bearing or wcb to qb, it can be reduced to the corresponding angle which is less than 90°.
• This type of angle is also known as a Reduced bearing.
• The examples of whole circle bearing are as follows.
  • 30°,45°,80°,120°,230°, and 320°, etc

Also, read: Prismatic Compass Survey Vs Surveyor Compass. | Least Count of Prismatic Compass & Surveyor Compass

What Is Quadrantal Bearin (QB)

The Quadrantal bearing, often referred to as reduced bearing in surveying, is also known as a Reduced bearing. Quadrantal bearings are generally measured from the North or South direction towards the East or West direction.

The quadrantal bearing or reduced bearing can be measured either in a clockwise or anticlockwise direction.

The quadrantal bearing varies from 0° to 90°.

In the quadrantal bearing or reduced bearing system, the bearings are taken either from the magnetic North or the magnetic south direction. It will depend on which one is nearer to that line.

In the Quadrantal bearing system, magnetic North and magnetic South lines are considered as reference line.

Example of Quadrantal Bearing

In the quadrantal bearing system, you can take both clockwise as well as anticlockwise angle from the reference line.

It is necessary to state the particular quadrant in which that line lies. The letters N(north), S(south), E(east), and W( west) are used to represent the quadrant.

Reduced bearing is observed by the surveyor’s compass.

The quadrants are represented are as follows.

• 1st quadrant = N – E
• 2nd quadrant = S – E
• 3rd quadrant = S – W
• 4^th quadrant = N – W

The example of the quadrantal bearing are as follows

• N35°E,S49°E,N65°W,S25°W etc.

Difference Between Whole Circle Bearing and Quadrantal Bearing

Understanding the difference between whole circle bearing and reduced bearing is crucial. The whole circle bearing and quadrantal bearing or reduced bearing are the two bearings that are usually used in the compass surveying.

In order to choose between the whole circle bearing and quadrantal bearing, you must know the difference between them.

he difference between the whole circle bearing and quadrantal bearing are as follows.

Observation of the Bearings

• When considering the whole circle bearing system in surveying, consider the bearing of the line is AB to be observed.
• Set up the instrument and at station A and then carry out the temporary adjustments.
• Fix one of the ranging rods at the station B.
• Turn the compass box until the ranging rod present at station B is not bisected by the horsehair when seen through the vertical slit above the prism.
• When the needle comes to rest, bisect it by the ranging rod at station B accurately and write down the reading.
• Hence you will get a bearing of the line AB.