Staff and its graduation
The aim of this tutorial is to demonstrate how to read a levelling staff that conforms to British Standard 4484.
Levelling
staff.
Two "E" pattern staffs are shown on the right, note slight differences in the marking and numbers. The "E" pattern is designed to make it easy to read a small section of the scale when seen through a telescope.
The staff is simply a large ruler, available in lengths of 3, 4 or 5 metres and usually made of aluminium with telescopic sections.
The sections have locking buttons to ensure accurate length is maintained.
Some staffs also have an extended length scale in mm on the back.
Measurements are in metres and cm (10mm blocks) which enable heights to be estimated to 1 mm. Alternating colours are used to differentiate each metre length, the most common being black and red on a white background.
Major graduations occur at 100 mm intervals and are denoted by figures. Minor graduations are at 10 mm intervals and form coloured squares or intervening spaces. The lower 50 mm of any 100 mm block are joined by a band to form the distinctive E pattern which is designed to make reading a small section of the staff in the telescope easier.
Example staff readings are shown below:
Now check your knowledge:
