Reasons why left swing is not favoured in theodolite survey:
- Parallax error: When the theodolite is swung from right to left, the observer's eye tends to move away from the eyepiece, causing parallax error. This error can lead to inaccurate measurements and affect the overall quality of the survey.
- Difficulty in reading vernier scales: Most theodolites have vernier scales that are easier to read when the instrument is swung from left to right. When the swing is in the opposite direction, it can be challenging to accurately read the scales, leading to errors in angular measurements.
- Unnatural movement for theodolite operators: Theodolite operators are trained to swing the instrument from left to right, as it is the standard practice in surveying. Swinging the theodolite in the opposite direction can feel unnatural and may result in slower and less precise measurements.
- Lack of standardization: Left swing is not a common practice in theodolite surveying, leading to a lack of standardization in procedures and techniques. This can cause confusion and inconsistencies in survey results when different operators use different swing directions.
- Risk of misalignment: Left swing can increase the risk of misalignment in the theodolite, especially for less experienced operators. Misalignment can result in skewed measurements and inaccurate data, compromising the integrity of the survey.
In conclusion, while there may be situations where left swing is unavoidable, it is generally not favoured in theodolite surveying due to the potential for errors, difficulties in reading scales, lack of standardization, and increased risk of misalignment. It is important for theodolite operators to follow established practices and guidelines to ensure accurate and reliable survey results.