Aquaculture Engineering (2+1)

Basic problems in chaining - To drop a perpendicular to chain line

Unit 1- Surveying

Basic Problems in chaining

To drop a perpendicular to chain line from a point outside it
I Method

AB is the chain line. It is required to drop a perpendicular to a chain line AB from point ‘D’ out side it. Select any point ‘E’ on the chain line. With ‘D’ as center, and DE as radius, draw an arc to cut the chain line at F. Bisect EF at ‘C’ and then CD is perpendicular to chain line AB.

II Method
Select any point E on the line (Fig(b)). Join ED and bisect it at F. With F as centre and EF or FD as radius, draw an arc to cut the chain line in C, CD will be perpendicular to the chain line.