The permissible error in chaining for measurement with chain on rough or hilly ground is ............

Cross staff is an instrument used for ............

The true meridian of a place is the line in which earth's surface in intersected by a plane through ............

If whole circle bearing of a line is 120°, its reduced bearing is ............

A staff reading taken on a bench mark or a point known elevation is called ............

In setting up a plane table at any station ............

An inverted level staff is held when ............

A deflection angle is ............

For true difference in elevations between two points A and B, the level must be set up ............