If L is the specified length of a tape, L1 its actual length and S the measured distance, then the true distance is given by the formula ............

The rise and fall method ............

For taking offsets with an optical square on the right hand side of the chain line, it is held ............

The least count of a vernier scale is ............

The main difference between an optical square and prism square is ............

A staff reading taken on a bench mark or a point known elevation is called ............

The instrument, belonging to a class of reflecting instrument is ............

If the whole circle bearing of a line is 120°, its quadrant bearing is ............

The true or geographical meridians through the various stations ............