Levelling Staff, Surveying and Levelling | Surveying and Levelling Notes- Agricultural Engg - Agricultural Engineering PDF Download

Levelling staff

It is an important accessory used with levelling instrument at the time of conducting levelling survey.  Reading is taken on the levelling staff held properly at the point concerned by viewing through the telescope of the levelling instrument.  Usually 4 m levelling staff may be used of folding type or telescopic type.  Aluminium levelling staff foldable at every metre length has also came to the market.  The levelling staff consists of three pieces.  The topmost one slides into the middle one and the middle portion slides into the bottom one.  When the staff is fully pulled, it will read exactly 40 decimeters (4m) from the bottom shoe.

Graduation in levelling staff:

•  Every metre length is divided into 200 divisions.

•  The divisions are painted in black and white alternately of thickness 5 mm each.

•  The graduation figures are marked at every decimeter length.

•  The number indicating metre is in red and the decimeter number is in black.

•  Thus, a graduation figure of 24 indicates 2 metres and 4 decimeters.

•  The graduation are made continuously one above the other in the same line.

•  The division lines should be parallel to the base of the bottom shoe and perpendicular to the length of the staff.

•  The edges of the division lines should be straight sharply defined.

•  They should be clear and made distinctly visible by properly contrasting.

•  The graduation colour paints used should not crack or blister when exposed to adverse or atmospheric conditions.