# Whole Circle Bearing (WCB) | Surveying

## In Whole circle bearing (WCB) / Azimuthal system - Bearings are measured clockwise from north of reference meridian

Bearing system is of two types - Whole circle bearing and reduced bearing. First let us understand what is meant by bearing and meridians.

### Bearing and Meridians

• Bearing of line : ​Direction with respect to a given meridian

• Meridian is a fixed reference line

### Types of meridian and bearing

True Meridian - Line through true north and south poles, and this remains constant throughout. To find out this line, we need astronomical observations.

• Bearing with respect to true meridian is known as true bearing

Magnetic Meridian - Direction indicated by freely suspended magnetic needle, and this magnetic N-S line changes with location and time as they are affected by earth’s magnetism.

• Bearing with respect to magnetic meridian is known as  magnetic bearing.

Arbitrary Meridian - Well defined reference object like a tower whose position is not going to change, directions are measured with respect to it and they are known as arbitrary bearings

### Whole Circle Bearing (WCB) / Azimuthal System

Bearings are measured clockwise from north of reference meridian

• It varies from 0 degrees to 360 degrees in the clockwise direction

• North will be zero degrees; East will be 90 degrees; South will be 180 degrees and West will be 270 degrees.

• Prismatic compass used WCB system

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