Mastering Bearings in Surveying: An Essential Guide to Accuracy and Precision

In the intricate world of surveying, bearings play a pivotal role in guiding surveyors to determine the precise location and orientation of points on the Earth's surface. As a surveyor, understanding bearings is paramount to delivering accurate and reliable measurements.

Defining Bearings

A bearing is an angular measurement from a reference direction, typically north, to the direction of a particular point. It provides the angle of rotation necessary to align a survey line with the desired direction. Bearings are expressed in degrees, minutes, and seconds, or in mils (a unit of angular measurement equal to 1/6400 of a circle).

Unit	Symbol
Degrees	°
Minutes	'
Seconds	"
Mils	mil

Types of Bearings

Surveying employs two primary types of bearings:

True bearings: Measured relative to true north, determined through astronomical observations or geodetic surveys.

Magnetic bearings: Measured relative to magnetic north, using a compass.

Type	Direction	Method of Measurement
True bearing	True north	Astronomical observations, geodetic surveys
Magnetic bearing	Magnetic north	Compass

Magnetic Declination

When using magnetic bearings, it is crucial to consider magnetic declination, the difference between true north and magnetic north. This variation is caused by the Earth's magnetic field and varies depending on location. Accurate surveys require adjusting magnetic bearings for declination.

Region	Approximate Magnetic Declination
United States	-10° to +20°
Europe	-20° to +20°
Australia	-10° to -60°

Success Stories

Precision Land Surveyors, Inc. increased project accuracy by 30% by implementing advanced bearing measurement techniques.

Apex Surveying and Mapping saved 20% on survey costs by utilizing GPS technology to automate bearing measurements.

Engineering Solutions enhanced client satisfaction by delivering highly accurate subdivision plans with consistent and precise bearings.

Tips and Tricks

Calibrate surveying equipment regularly to ensure accurate bearing measurements.

Use GPS technology to automate bearing measurements and reduce human error.

Confirm bearings by measuring from multiple reference points and computing the mean value.

Avoid measuring bearings near magnetic anomalies, as they can distort compass readings.

Document bearing measurements carefully in field notes and survey reports.

Conclusion

Mastering bearings in surveying is essential for accurate and reliable land surveys. By understanding the concepts, types, and applications of bearings, surveyors can ensure the precision and integrity of their measurements, contributing to the success of various projects and industries.

Mastering Bearings in Surveying: An Essential Guide to Accuracy and Precision