Filter
Top Products
13
The task is to measure the
height of a pillar at a distance
of 25 m [82 ft] on level ground
(Fig. 8).
The instrument is tilted so that
the hairline is seen against the
pillar-top (apex). The reading
obtained will be 48 % (ca
25 ½°), As the distance is
25 m [82 ft] the height of the
pillar is 48 / 100 x 25 = ca.
12 m [48 / 100 x 82 ft = ca.
39 ft]. To this must be added
the eye's height from the
ground, e.g., 1.6 m [5 ½ ft].
Their sum is 13.6 m [44 ½ ft],
the height of the pillar.
In very exact measurements,
and particularly on sloping
ground two readings are
taken, one to the top, the other
to the base of the pillar. When
the pillar base is below eye
level the percentages ob-
tained are added. The total
height is the sum percentage
25 m [82 ft]
12 m
[38 ft]
1.6 m
[5½ ft]
48 %
25 ½°
25 m [82 ft]
3.25 m
[10½ ft]
41%
10.25 m
[33½ ft]
13.5 m
[44½ ft]
13%
Fig. 8. Measuring height of a pillar
Fig. 9. Taking two readings