Errors Concepts in Surveying Engineering

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Errors Concepts in Surveying Engineering

Nerxon publication, Published date: Nov.2022

Surveying is a set of calculations and measurements that result in the creation of a map. In any surveying operation, the presence of errors (systematic and random errors) is certain and unavoidable. By analyzing these errors, we can achieve the desired accuracy in measurements, and it is evident that precise measurements lead to accurate calculations. Instead of using expensive equipment and wasting time, we can employ methods that achieve suitable accuracy with minimal effort and cost. The measurements we obtain have slight differences from the actual values, and this difference is referred to as an error. The major sources of these errors include:

Natural Factors:

Temperature changes, light refraction, wind, ground variations, etc.

Human Factors:

Lack of skill and experience in the work, disruption of human senses such as vision and hearing, etc.

Instrumental Factors:

These result from technical deficiencies or improper calibration of the equipment. By identifying the problem and applying an appropriate method and necessary corrections, we can eliminate its effects.

Errors are classified into three categories:

Outliers
Systematic or Gradual Errors
Random or Accidental Errors

Outliers:

These are errors that occur due to carelessness, inattention, or lack of experience. These types of errors must be completely eliminated from the calculations. To identify Outliers in surveying operations, one can perform the operation in a forward and backward manner.

Systematic Errors:

These are errors that follow a specific pattern, with known causes and magnitudes. The magnitude and direction of these errors remain consistent under similar measurement conditions. Examples include ionospheric and tropospheric errors. For instance, weighing scales with systematic errors will consistently show a person’s weight as either more or less than their actual weight. Collimation error (error in the line of sight of a camera) is considered a systematic error and occurs when the camera is leveled, but the line of sight is not horizontal.

Random Errors:

Even after eliminating the above errors, some measurement errors still persist, which are referred to as random errors. These errors are unpredictable and cannot be corrected or calculated. Causes may include limitations of human senses, insufficient precision, or defects in the measuring instrument.

Outliers are usually large and traceable, making them possible to eliminate or correct, and with proper control, they can be prevented.
Errors are generally small and sometimes uncontrollable or uncorrectable.

References:

Schofield, W., & Breach, M. (2007). Engineering Surveying (6th ed.). CRC Press. https://doi.org/10.1201/9781315147048
Roy, S K. Fundamentals of Surveying. New Delhi, Phi Learning, 2010.
Chandra, A M. Surveying. New Age International, 2005

Types of Coordinate Determination Methods

1 Response

droversointeru says:

December 24, 2024 at 8:28 pm

Very interesting topic, thankyou for putting up. “Nobody outside of a baby carriage or a judge’s chamber believes in an unprejudiced point of view.” by Lillian Hellman.

https://www.droversointeru.com

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