- Levelling staffs are made of wood, metal or glass fibre and graduated in metres and decimals.
- The alternate metre lengths are in black and red on a white background.
- The majority of staffs are telescopic or socketed in three sections for easy carrying. Although the graduations can take various forms, the type adopted in the UK is the British Standard (BS 4484) E-pattern type as show in fig.
- The smallest graduation on the Levelling staff is 0.01 m, with readings estimated to the nearest millimetre.
- As the staff must be held vertical during observation it should be fitted with a
As stated in the definition of levelling, the object is
(i) to determine the elevations of given points with respect to a datum
(ii) to establish the points of required height above or below the datum line.
Uses of levelling are
(i) to determine or to set the plinth level of a building.
(ii) to decide or set the road, railway, canal or sewage line alignment.
(iii) to determine or to set various levels of dams, towers, etc.
(iv) to determine the capacity of a reservoir.