Line of collimation

A 'level line' is a

Isogonics lines are the lines having the same

A Bench mark is a

A tape of length l and weight 'w' kg/m is suspended at its ends with a pull of P kg, the sag correction is,

In route surveys, the most suitable method of contouring is

For the construction of highway

While measuring a chain line between two stations intervened by a raised ground

The least count of a vernier scale is