The process of turning the telescope about the vertical axis in horizontal plane is known as ............

Imaginary line passing through points having equal magnetic declination is termed as ............

The instrument used for setting out an offset at a right angle, is called ............

When the measured length is less than the actual length, the error is known as ............

Benchmark is established by ............

The difference in the length of an arc and its subtended chord on the earth surface for a distance of 18.2 km, is only .…

The limiting length of the offset is ............ when its perpendicular direction is set out by an eye.

An angle between the inclined line of sight and the horizontal is called ............

The accuracy in laying down the perpendicular offsets and in measuring them depends upon ............