The errors affecting linear measurements
are so numerous, of such a variable nature and so
inter -connected, that the ultimate accuracy of
measuring distances is more difficult to assess than
that of any other surveying operation. The greatest
source of trouble is the pronounced interference of
cumulative errors due principally to using an
incorrect chain or tape, disregarding slòpe, poor
alignment, the unevenness of the ground and the effect
of sag.The care with which the measurements are
made is also an important factor, and in many cases,
in mine surveying particularly, the operation of
measuring is left in the hands of unskilled workmen,
and appreciable marking and reading errors are introduced
