Name: survey direction with azimuths and bearings
Uploaded: 2025-03-26T15:20:02.000Z
Duration: 1 min 19 s
Channel: JoVE

The azimuth of a line is the clockwise angle from the north end of the reference meridian, typically used in plane surveys.The magnitude of an azimuth can range from zero to 360 degrees.For example, the forward azimuth of line AB is 55 degrees. To find the back azimuth or the azimuth of line BA, add 180 degrees to get 235 degrees.The bearing of a line is expressed as a reference direction, an angle of inclination, and the direction in which the inclination is measured.The reference directions are always the north or south ends of the meridian, and the angle is always 90 degrees or less.The bearing of line AB is North 55 degrees East, meaning the line is inclined 55 degrees eastward from the north. Similarly, the bearing of line BA is South 55 degrees West, found by reversing the directions of the bearing of AB.When a line moves through different quadrants, only the angle changes for its azimuth. In contrast, for bearings, both the reference direction and the direction of inclination change along with the angle.

azimuths and bearings

Azimuths and bearings are essential concepts in surveying, providing methods to express the direction of a line relative to a meridian.&nbsp;Azimuths&nbsp;refer to the clockwise angle measured from the north end of a reference meridian to the given line, ranging from zero to 360 degrees. This method gives a comprehensive directional reference within a full 360-degree circle, making it a straightforward way to communicate direction in various fields, including navigation, cartography, and construction.Bearings, in contrast, offer a more segmented approach by indicating direction within one of four quadrants formed by the north-south and east-west axes. Bearing measurements include a reference direction, an inclination angle, and a direction of inclination, such as northeast or southwest. The bearing angle is always under 90 degrees, making this method ideal for detailing direction within a specific quadrant. While azimuths change only in angle as lines move through quadrants, bearings adjust the reference direction, angle, and inclination.&nbsp;Both azimuths and bearings are crucial in precise location mapping, where defining exact line orientation is essential for planning, property demarcation, and alignment in infrastructure development. Their use provides clarity and precision, ensuring that directions and positions are understood universally across surveying applications.

Azimuths and Bearings

Azimuths and bearings are essential concepts in surveying, providing methods to express the direction of a line relative to a ...

Education

JoVE Core

Civil Engineering

Unit 1

Angles and Directions

KEY TERMS AND CONCEPTS

survey direction with azimuths and bearings

Azimuths and bearings are key ways to describe direction in surveying. They show the position of a line relative to a meridian, which is a reference north-south line. Surveyors use these measurements to communicate direction clearly and consistently.

An azimuth is the clockwise angle measured from the north end of the reference meridian to the line being studied. It ranges from 0 to 360 degrees, so it gives a full-circle direction. This makes azimuth useful in navigation, cartography, and construction.

A bearing uses a different system. It describes direction within one of four quadrants made by the north-south and east-west axes. A bearing includes a reference direction, an angle of inclination, and the direction of inclination, such as northeast or southwest. The angle is always less than 90 degrees.

Azimuths and bearings both help map lines with precision. As a line moves through quadrants, an azimuth changes only by its angle. A bearing changes the reference direction, the angle, and the inclination. These methods are important for planning, property demarcation, and alignment in infrastructure work.

Survey Direction with Azimuths and Bearings

survey-direction-with-azimuths-and-bearings

meridians

Survey Meridians for Direction Control

Survey meridians are reference lines that help surveyors measure direction and set land orientation. They run from the north pole to the south pole and give surveys a stable frame for angular measurements and mapping. In survey design, meridians are chosen based on the size of the project and the level of precision needed. An astronomic meridian is tied to astronomic north, which is based on Earth’s axis and gravity. Surveyors determine it through celestial observations, often by using...

Azimuths and bearings are key ways to describe direction in surveying. They show the position of a line relative to a meridian, which is a reference north-south line. Surveyors use these measurements to communicate direction clearly and consistently. An azimuth is the clockwise angle measured from the north end of the reference meridian to the line being studied. It ranges from 0 to 360 degrees, so it gives a full-circle direction. This makes azimuth useful in navigation, cartography, and...

compass

Compass Bearings and Magnetic North

The compass is a navigation tool that uses Earth's magnetic field. Its magnetic needle lines up with magnetic north, which helps people find direction and stay oriented. Because magnetic north is not exactly the same as true north, a compass shows a slightly different direction than geographic north. That difference is called magnetic declination. Declination is the angle between magnetic north and true north, and it changes with location. It can also change over time because Earth's magnetic...

magnetic declination

Compass Error and Magnetic Declination

Magnetic declination is the angle between true north and magnetic north. True north points along Earth’s rotational axis. Magnetic north follows Earth’s magnetic field. Because the magnetic poles do not match the geographic poles, a compass does not point exactly toward true north. The size of magnetic declination depends on where an observer is located on Earth. It also changes over time because Earth’s magnetic field is dynamic. Declination is called eastern when magnetic north lies east of...

local attraction

Compass Errors from Nearby Magnetic Objects

Local attraction is a compass error caused by nearby magnetic influences. Metal fences, buried pipes, vehicles, buildings, power lines, and natural iron ore deposits can all disturb the compass. Small items such as wristwatches, steel tools, and belt buckles may also create local magnetic fields that bend the Earth's magnetic field and affect the reading. These disturbances make compass readings inaccurate. That can create problems in navigation and land surveying. Surveyors look for local...

design example: traverse angle computations

design-example-traverse-angle-computations

Closed Traverse Angle Checks

Closed traverse angle checks are used in surveying to calculate the internal angles inside a closed loop. A traverse is a set of connected lines that return to the starting point. Surveyors use it for land boundary mapping and other layout work. The process starts with known azimuths and bearings for the traverse sides. An azimuth is a direction measured from north, and a bearing shows the direction of a line in simple survey terms. Internal angles at each vertex are then found with basic...

key terms and concepts

Learn how azimuths and bearings describe direction in surveying, from 0–360 degree azimuths to quadrant-based bearings used in mapping and construction.

Survey Direction with Azimuths and Bearings | JoVE K12

JoVE Core Civil Engineering offers a foundational exploration of essential construction materials such as bricks, stones, steel, wood, and concrete, along with fluid mechanics topics like flow over immersed bodies, open channel flow, and dimensional modeling. It also covers key surveying concepts, including leveling, traverse adjustments, curve design, topographic mapping, and geospatial technologies (GPS & GIS). Science-in-action videos showcase laboratory research on materials, fluids, and surveying practices in real-world engineering systems.

Survey Direction with Azimuths and Bearings

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