Example 2: You desire a negative 1.5% slope and your level reading is 1.459m on a staff that is
20m from your laser.
Eg: -1.5% Slope with Point A 20 metres from the laser. (Note: -1.5% = -1.5/100)
Height Differential = (slope %) x (distance)
= (-1.5%) x (20m)
= (-1.5/100) x (20m)
= -0.300m
To establish your required “slope” reading on the staff add the Height Differential to the original
“level” reading:
Required “slope” reading on staff = original “level” reading + Height Differential
= 1.459m + (-0.300m)
= 1.459m – 0.300m
= 1.159m
— 23 —
To Next Page