To instrument resembling an alidade is ............

In locating the details of inaccessible objects visible at least from transit stations, the method used is ............

The diaphragm of a stadia theodolite is fitted with two additional ............

The line normal to the plumb line is known as ............

A series of closely spaced contour lines represents a ............

An instrument that can be used as an optical square ............

In route surveys, the most suitable method of contouring is ............

The ranging of the line between two stations across raised ground is called ............

Correction for pull is ............