Title 113 Errors in Leveling.pdf ✅

MSTC 113: Errors in Leveling Let eB and eF be the errors in leveling on the backsight and foresight, respectively. Therefore, applying corrections to the equation for the difference in elevation (assuming subtractive values for the corrections) ΔElevation = (BS − eB) − (FS − eF ) ΔElevation = (BS − FS) + (eF − eB) The succeeding parts show the possible sources of leveling errors. 1. Settling of Rods Notice that when a rod settles down, then the reading increases. Therefore, the error is treated like the original equation for the leveling errors. ΔElevation = (BS − FS) + (eF − eB) 2. Inclining Rods From trigonometry, R = R ′ cos θ The formula for the error is e = R ′ − R e = R ′ − R ′ cos θ Therefore, e = R ′ (1 − cos θ) This applies to both backsight and foresight.