SUUNTO Tandem - Manual (Page 15)

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of the horizontal distance. For example (Fig. 9), if the apex reading is 41 % and the
ground reading 13 %, the total height of the pillar measured from a distance of 25 m
[82 ft] is (41 + 13) / 100 x 25 m = 54 / 100 x 25 m = ca. 13.5 m [(41 + 13)/100 x 82 ft =
54/100 x 82 ft = ca. 44 ½ ft].
When the pillar base is above eye level, the base reading is subtracted from the apex
reading, and the total height is the difference percentage of the horizontal distance.
For example (Fig. 10), if the apex reading is 64 % and the base reading 14 %, the
total height is (64 – 14) / 100 x 25 m = 50 / 100 x 25 m = 12.5 m [(64 – 14) / 100 x 82 ft
= 50 / 100 x 82 ft = 41 ft]. When calculations are made mentally, it is advisable to use
measuring distances of 50, 100 or 200 ft, for the sake of simplicity.
Fig. 10. Pillar above eye level
3.5 m
[11½ ft]
64%
12.5 m
[33½ ft]
14%
25 m [82 ft]