26.2
Azimuths and Bearings
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 are essential concepts in surveying, providing methods to express the direction of a line relative to a meridian.
Azimuths 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.
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.
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.
From Chapter 26:
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26.2 : Azimuths and Bearings
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26.1 : Meridians
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26.3 : Compass
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26.5 : Local Attraction
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26.6 : Design Example: Traverse Angle Computations
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