1. **Problem Statement:** We are given a profile leveling scenario with stations A to H and a datum at station A with elevation 240. We need to write the major steps of profile leveling and label stations A-H using profile leveling knowledge. 2. **Major Steps of Profile Leveling:** - Set up the leveling instrument at a point where you can see the backsight (BS) and foresight (FS) points. - Take a backsight reading (BS) on a known elevation point or benchmark. - Take intermediate sight (IS) readings on points between BS and FS if needed. - Take a foresight reading (FS) on the next point where the instrument will be moved. - Calculate the rise or fall between stations using the difference between BS, IS, and FS readings. - Compute the reduced level (RL) of each station using the datum and the rise and fall values. - Move the instrument to the next setup point and repeat the process until all points are leveled. 3. **Labeling Stations A-H:** - Station A is the datum with RL = 240. - Stations B and C are forward points with FS readings. - Station D is the instrument setup point with BS and IS readings. - Stations E, F, G, and H are subsequent points with BS, IS, and FS readings as per the leveling process. 4. **Explanation:** - The backsight (BS) is the reading taken on a point of known elevation. - The foresight (FS) is the reading taken on a point where the instrument will be moved next. - Intermediate sights (IS) are readings taken on points between BS and FS. - Rise and fall are calculated by comparing consecutive readings to determine if the ground level rises or falls. - Reduced levels (RL) are calculated by adding rises or subtracting falls from the known datum elevation. 5. **Summary:** Profile leveling involves systematic readings of BS, IS, and FS to determine the elevation profile of a terrain relative to a datum.