By insideSail
Automated technical check · version 1 ·
Azimuth and bearing: where does the angle start?
A direction needs a reference, an observer and a reading convention.
In this guide
Original schematic illustration. Read the explanation and limitations in the lesson.
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In navigation, a bearing describes an object’s direction from an observer. Azimuth names angular directions and also appears in astronomical and surveying contexts. Terms and conventions vary between documents; this lesson states the drawing’s convention instead of assuming they are all identical.
A direction is not a position
A line pointing to an object does not, by itself, say how far away it is. Different objects can lie in the same direction. Likewise, the direction of an object is not automatically the heading along which someone intends to steer.
Read the label attached to an angle: true, magnetic, compass or relative. A relative bearing uses the boat’s axis as its reference and is not directly the same number measured from north. Recognising these words prepares you to read instruments; conversions and position fixing require separate teaching and checking.
Concepts in this lesson
Azimuth
A horizontal angular direction with a stated reference and measurement convention.
Bearing
An object’s direction from an observer, relative to the stated reference direction.
Sources and references
- S-32 — Hydrographic Dictionary: azimuth ↗
International Hydrographic Organization · Online hydrographic dictionary · Entry 331: azimuth; reference direction and angular convention
Version: Online hydrographic dictionary. Jurisdiction: International.
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