Errors in Chain Surveying – Civil Engineering Projects

A practical Example for Calculation of the True Area of the field | Errors in Chain Surveying

In my previous article, we studied how to measure true distance considering the Errors occurring in Surveying.

Correction formulas to be kept in mind (for incorrect length of Chain)

True distance = L’/L*measured distance

True area = (L’/L)2*measured area

True Volume = (L’/L)3 * measured volume

Where, L’ = incorrect length of chain

L = correct length of chain

The chain was tested before starting the surveying and was found to be 20m. At the end of surveying, it was tested again and was found to be 20.12m. The area of the plan of the field drawn to a scale 1cm = 6m was 50.4sqm. Find the true area of the field in sqcm.

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Numerical Examples for Errors in Chain Surveying

We will now move on with different numerical problems on the concept of Errors in Chain Surveying. Going through these numericals will actually give you an idea as to how the calculations are done inspite of errors occurring in the Chain Surveying.

Correction due to incorrect length of chain

This is like a formula list which is to be kept in mind while making Calculations:

True distance = L’/L*measured distance

True area = (L’/L)2*measured area

True Volume = (L’/L)3 * measured volume

Where, L’ = incorrect length of chain

L = correct length of chain

The length of a line measured with 20m chain was found to be 500m. It was subsequently found that the chain was 0.04m too long. What is the length of line?

Correct length of chain, L’ = 20 + 0.04 = 20.04m

Length, L = 20m