The process of turning the telescope of a theodolite over its supporting axis through 180° in a vertical plane, is called ............

Setting out of a simple curve by two theodolite method does not require ............

A line normal to the plumb line at all points is known as ............

The principle of tacheometry is used ............

In reciprocal leveling, the error which is not completely eliminated, is due to ............

The surface if zero elevation around the earth, which is slightly irregular and curved, is known as ............

The length of a link of Gunter's chain is ............

The adjustable cross-staff is used for setting out an offset ............

When the first object is to be focused, the scale is set to 0°00'00" and then ............