During secular variation of magnetic meridian at different places ............

In a theodolite the line of collimation is ............

Indirect ranging is adopted when the two ends of chain line are ............

Chain surveying is most suitable when ............

The horizon glass of the box sextant is ............

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

Contour interval, within the limits of a map ............

The angle of field of the telescope ............

Ranging in chain survey means ............