Question

Thank you for your answer.
Can you please explain to me the concept of chain length

Answer 1

Chains are used to measure linear distance in a traverse. Each chain is formed by joining number of links using ring. This ring gives the flexibility to the chaining work. The distance between the centre of one ring to the next ring is the length of one link. There is a handle provided at each end . By adding the length of each link we will get the length of each chain. So the length of one chain is distance from outside handle on one side to the outside handle of other side.

There are different types of chain available in the market depending on the length of the chain.-

A)Metric chain-These are of length 5m,10m,20m,30m.These chains are called metric chain because their unit of measurement is metre.

B)Gunter's chain-It is also called surveyors chain.It's length is 66ft and it consists 100 link.Length of each link is 0.6 ft.

C)Engineer's chain-It is of 100ft length and 100 link.The length of each link is 1 ft.

D)Revenue Chain-It's length is 33 ft and there is 16 link in revenue chain. The length of each link is 2.0625 ft.

Error in chain length- There may be error in traversing length due to change in length of chain. Length of chain may change due to the temperature change as these chain are made up of metal which changes it's length with the change in temperature. If the length of chain is too short to its designated length then the measured length using this chain will be more. So the error will be positive and correction will be negative.If the length of chain is too long to the designated length then measured distance will be less .The error in measurement will be negative so positive correction need to be applied.