Grid lines are parallel to ............

A fixed point of reference of known elevation is called ............

Centering error of a theodolite produces an error ............

The number of horizontal cross wires in a stadia diaphrgram is ............

Accuracy of elevation of various points obtained from contour map is limited to ............

The altitude of a traverse leg is obtained by multiplying its length by ............

The lines of earth's magnetic field run from ............

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

In case of a direct vernier scale ............