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.
Scale of the plan
1cm = 6m
1cm2 = 36m2
Area of plank = 50.4 cm2
Measured area of field = 50.4 * 36
= 1814.4m2
Incorrect length of chain, L’ = (20+20.12)/2
= 20.06m
L = 20m
True area = (L’/L)2 * measured area
= (20.06/20)2 * 1814.4
= 1825.3m2
1 hectare = 10,000m2
= 0.1825 hectare
It explained the concept well bt needed more numericals. Here explained only one.