Fly levelling
it is a very approximate form of levelling in which sights are taken as largeas possible. In this method a line of levels is run to determine approximately reduced levelsof the points carried out with more rapidly and less precision. It is a levelling that is done toconnect benchmark to the starting point of the survey line. In this levelling only back sightand fore sight readings are taken and auto level is moved strictly on the line joining benchmark and starting point of survey line

The capacity of doing work by an artisan or skilled labour in the form of quantity of work per day is known as the task work or out turn of the labour.

The out-turn of work per artisan varies to some extent according to the nature, size, height, situation, location, etc., In bigger cities where specialized and experienced labour is available the out-turn is greater than small towns and country sides.  In well organized work less labour is required.