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4.3 Measuring Height Difference
(1) Set up the instrument at a point approximately halfway between
points A and B. See (Fig 4.3A).
NOTE: The reticle stadia lines can be used to optically estimate
the distances. See (Fig 4.2A)
(2) Position the rod vertically at point A. Take the reading
a
(backsight)
on the rod at point A.
(3) Then sight the rod at point B and take the reading
b
(foresight).
(4) The difference (
a-b
) is the height difference (h) of B from A. (Fig 4.3A)
Example:
h=
a-b
=5.25ft-3.25ft =2.00ft
Therefore point B is 2.00ft higher than point A. (the value of h will be
