How to use cross staff in surveying?

You can use cross-staff by using the following method:

• The cross staff is an instrument that helps in the calculation of right angles.
• The cross staff is simple with a pointed end so that is can easily be set into the ground.
• On its top there is a square block of wood, and there is a pair of grooves.
• To calculate the right angle with the cross staff, set it exactly at the point on the survey line from which the right angle has to be calculated.
• With one of the grooves pointing to the ranging rod at the end of the survey line.
• When citing the rods note that you should be able to see the centre of the rod.
• When citing it through the grooves also you should be able to see the surface of cross staffs block and the ranging rod.
• Nothing else between them in the correct position the grooves should be pointing straight to the centre of the rod.
• Through the other grooves site the other ranging rod which must be held by another surveyor.
• Use ranging signals so that you can have it set exactly in line of sight through the other groove.
• As the groove of the block crossed off lying at right angles to each other we can say that the ranging rods sighted through each of these grooves also lie at the right angles to each other.
• So, remember you can calculate right angles with the cross staff by citing an object through one pair of grooves and sighting another object through the other pair of grooves.