Cumulative Errors

The errors that take place always in the same direction are known cumulative errors. In each reading the error can be small, but since the error is always on one side while large number of measurements is made they may be considerable,. Instance of such errors are:

1.      Bad straightening

2.      Bad ranging

3.      Temperature variation

4.      Erroneous length of chain

5.      Variation in applied pull

6.      Non-horizontality

7.      Sag in the chain, for measuring horizontal distance on a sloping ground if suspended.

Errors (i), (ii), (vi) and (vii) are always +positive since they make measured length more than actual. Errors (iii), (iv) and (v) may be positive or negative.