What is Rise and Fall method in Surveying
Rise and Fall Method in Surveying
Surveying is required to accurately determine the size, shape, and elevation of the Earth’s surface.
The rise and fall method is a levelling technique used in surveying to determine the difference in elevation between two points. We must compute the difference in the staff’s elevation at the two points using this method. We know the RL of ground for one of the two stations where the staff readings are taken, but we need to locate the RL of the other station.
The rise and Fall method
It is a method for calculating the difference in elevation between two consecutive points by comparing each point after the one immediately preceding it. The difference in staff readings indicates a rise and fall. Following that, RL is calculated by adding the rise to or subtracting the fall from the previous point’s reduced level.
Method to calculate R.L(Reduced Level)
fall (F) = foresight (F.S.) — backsight (B.S.)
fall (F) = intermediate sight (I.S.) — backsight (B.S.)
rise (R) = backsight (B.S.) — foresight (F.S.)
reduced level (R.L.) = precede reduced level + rise (R)
reduced level (R.L.) = precede reduce level — fall (F)
