If the back sight and fore sight distance are kept equal during levelling observations, then the effect of both refraction and earth's curvature will be

Straight, parallel and widely spaced contours represent

The walk step of a man is considered equal to:

A tape of length l and weight 'w' kg/m is suspended at its ends with a pull of P kg, the sag correction is,

Profile levelling is usually done for determining

In a closed traverse, sum of south latitudes exceeds the sum of north latitudes and the sum of east departures exceeds t…

An example for instrumental error in levelling is

Cross-staff is used for

An obstacle which obstructs both chaining and ranging may be