Define the following terms in surveying: Levelling, Reduced level (RL), Height of plane of collimation (HPC). Also list two differences between open and closed traverse.

Here are the answers to Question 2: a) Define the following terms in surveying: i) Levelling: The process of determining the relative heights or elevations of points on or near the Earth's surface, typically with respect to a common datum. ii) Reduced level (RL): The vertical distance of a point above or below a specified datum surface, such as mean sea level. iii) Height of plane of collimation (HPC): The elevation of the line of sight of the levelling instrument above the datum. It is calculated by adding the backsight reading to the reduced level of the point where the instrument is set up. b) Two (02) differences between open and closed traverse: • An *open traverse