Types of Bearings

Types of Bearings 

It is an angle made by the survey line with reference to some fixed meridian.

Bearings are classified into three types:

1. True bearing
2. Magnetic bearing
3. Arbitrary Bearing

True bearing

The angle made by a survey line with reference to the meridian is known as true bearing. It always remains constant.

Magnetic bearing

The angle made by a survey line with respect to magnetic meridian is known as magnetic bearing. It changes from place to place.

Arbitrary Bearing

The angle made by the survey line with reference to arbitrary meridian is known as Arbitrary Bearing.

Designation of Bearings

1. Whole circle bearing
2. Reduced Bearing (RB) or quadrantal bearing (QB)
3. Fore Bearing (FB) or forward bearing (FB)
4. Back bearing or Backward bearing (BB)
5. Calculated bearing

Designation of Bearings | Guide to Compass Surveying

In my previous article, I discussed different types of Bearings in Compass Surveying. In this article, we will discuss in brief different designations given to the bearings depending on measurement of angles.

Designation of Bearings

1. Whole circle bearing
2. Reduced Bearing (RB) or quadrantal bearing (QB)
3. Fore Bearing (FB) or forward bearing (FB)
4. Back bearing or Backward bearing (BB)
5. Calculated bearing

Whole Circle bearing

Bearings measured from north in a clockwise direction is termed as whole circle bearing.

The value varies from 0 degrees to 360 degrees.

Reduced bearing/Quadrantal bearing

The bearings measured either from the north or from the south towards east or west whichever is nearer is known as reduced bearing.

The values vary from 0 degrees to 90 degrees for a particular quadrant.

It is also known as quadrantal bearing (QB).

Fore Bearing (FB)

The bearings measured in the progress of surveying i.e. in the forward direction of survey lines is known as forebearing or forward bearing.

Back Bearing (BB)

The bearings measured in opposite to the progress of surveying i.e. in backward direction of survey line is known as Backward Bearing.

Observed Bearing

The bearings taken in a field with an instrument is known as Observed Bearing.

Calculated Bearing

The bearings calculated from the field observation is known as calculated bearing.