Suunto PM5 Manuel d'utilisateur télécharger pdf (Page 12)

The task is to measure the

height of a tree at a distance of

25 m / 82 ft. on level ground.

The instrument is tilted so that

the hair line is seen against the

tree-top (apex). The reading

obtained will be 48 per cent (ca

25.5°). As the distance is 25 m /

82 ft. the height of the tree is 48

/ 100 x 25 m = ca. 12 m or

equally 48 / 100 x 25 m = ca. 12

m or equally 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 or 5 ½ ft.

Their sum is 13.6 m or 44 ½ ft,

the height of the tree.

In very exact measurements,

and particularly on sloping

ground two readings are taken,

one to the top, the other to the base of the trunk. When the trunk base is below eye

level the percentages obtained are added. The total height is the sum percentage of

the horizontal distance. For example, it the apex reading is 41 % and the ground

reading 13 %, the total height of the tree 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 or equally in feet (41 + 13) / 100

x 82 ft = 54 / 100 x 82 ft = ca. 44 ½ ft.

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Suunto PM5 Manuel d'utilisateur Page 12