When the bubble of the level tube of a level, remains central

Total station is

An imaginary line on the surface of the earth having a constant inclination with the horizontal (slope) is called

The fundamental principle of surveying is to work from the

One mile equals to

Closed contours with higher value inside represents a

The method of plane tabling commonly used for establishing the instrument stations only, is a

An imaginary line lying throughout on the surface of the earth and preserving a constant inclination to the horizontal, …

How many types of bench mark are there?