Line ranging direct and indirect

Ranging a line means establishing intermediate points on the line. This can be accomplished with visual observations and range rods, by sighting through an instrument called a ‘line ranger’ or by sighting a theodolite in precision work for long lines. Operations can be classified as follows:Direct ranging

Indirect ranging

Indirect Ranging: Here, the surveyor cannot find out any intermediate points on the line on his own and has to depend upon the statement of a person at the end of the line and also on the statement of the person carrying the ranging rod.

Direct Ranging: In direct ranging, the surveyor can observe and direct the person holding the ranging rod to put the ranging rod at any intermediate point on the line being ranged out.