The position of point can be fixed more accurately by

Due to curvature of earth the object

Different types of EDM's are obtained on the basis of

The length of an Engineer's chain is

An invert is taken when the point is

A freely floating needle slightly gets inclined to the horizontal anywhere except on the equator. It is called

In a theodolite the line of collimation is

The first reading from a level station is

Levelling across a river is done by