# Clinometer

**Topics:**Measurement, Units of measurement, Analytic geometry

**Pages:**2 (593 words)

**Published:**March 7, 2011

Clinometer (forestry)

From Wikipedia, the free encyclopedia

A clinometer used in forestry

The clinometer, known in many fields as an inclinometer, is a common tool used in forestry to measure slope, vertical angles, and – in combination with distance measurements – elevation change or tree heights. Contents [hide] * 1 How it works * 2 Units of measure * 3 Tree height measurement * 4 Slope measurement * 5 Manufacturers * 6 See also * 7 References| -------------------------------------------------

[edit]How it works

A forester using a clinometer makes use of basic trigonometry. First the observer measures a straight-line distance D from some observation point O to the object. Then, using the clinometer, the observer measures the angle a between O and the top of the object. Then the observer does the same for the angle b between O and the bottom of the object. Multiplying D by the tangent of a gives the height of the object above the observer, and by the tangent of b the depth of the object below the observer. Adding the two of course gives the total height (H) of the object, in the same units as D.[1] Note that since multiplication is distributive it is equally valid to add the tangents of the angles and then multiply them by D: A = tan a

B = tan b

H = (A × D) + (B × D) = (A + B) × D

Note also that both angles should be positive numbers (i.e. ignore any minus sign on the clinometer's scale). -------------------------------------------------

[edit]Units of measure

There are typically three different units of measure that can be marked on a clinometer: degrees, percent, and topo. When buying a clinometer it is important to make sure it is calibrated to units suitable for the intended use. -------------------------------------------------

[edit]Tree height measurement

[[Image:Illustration of the basic trigonometric principles used by a clinometer.JPG|right|200px|thumb|Tree height...

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