Why do you measure both circle left and circle right in surveying?

In surveying, measuring both circle left and circle right ensures accuracy and reliability in determining angles and positions. By conducting measurements in both directions, surveyors can identify and correct any systematic errors or biases that may occur in the equipment or methodology. This practice helps to improve the overall precision of the survey and provides a check against potential mistakes. Additionally, it allows for a more comprehensive understanding of the terrain being surveyed.