Difference between revisions of "AY Honors/Forestry/Answer Key"

From Pathfinder Wiki
< AY Honors‎ | ForestryAY Honors/Forestry/Answer Key
(2 intermediate revisions by the same user not shown)
Line 1: Line 1:
−
[[Image:Stanley_compass_1.jpg|thumb|right|200px|Compass with inclinometer]]
+
[[Image:Clinometer commonly used by foresters.JPG|right|200px|thumb|A clinometer used in forestry]]
−
An '''inclinometer''' or '''clinometer''' is an instrument for measuring angles of [[slope]] (or [[tilt]]), [[elevation]] or [[inclination]] of an object with respect to gravity. It is also known as a ''tilt meter'', ''tilt indicator'', ''slope alert'', ''slope gauge'', ''gradient meter'', ''gradiometer'', ''level gauge'', ''level meter'', ''declinometer'', and ''pitch & roll indicator''.
+
The '''clinometer''', known in many fields as an [[inclinometer]], is a common tool used in [[forestry]] to measure [[slope]], [[vertical (angles)|vertical angles]], and &ndash; in combination with distance measurements &ndash; elevation change or tree heights.
−
Clinometers measure both inclines (positive slopes, as seen by an observer looking upwards) and declines (negative slopes, as seen by an observer looking downward).
 
  
−
In aircraft, the "ball" in [[turn coordinator]]s or [[turn and bank indicator]]s is sometimes referred to as an inclinometer.
+
==How it works==
 +
A forester using a clinometer makes use of basic [[trigonometry]].
  
−
==History==
+
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  [[Trigonometric_functions#Right_triangle_definitions|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''.<ref>[http://mysite.du.edu/~jcalvert/astro/abney.htm Calvert, J.B. “The Clinometer.” 2003.]</ref>
−
Early [[inclinometer]]s include examples such as [[Well's inclinometer]], the essential parts of which are a flat side, or base, on which it stands, and a hollow disk just half filled with some heavy liquid. The glass face of the disk is surrounded by a graduated scale that marks the angle at which the surface of the liquid stands, with reference to the flat base. The line 0.&mdash;0. being parallel to the base, when the liquid stands on that line, the flat side is horizontal; the line 90.&mdash;90. being perpendicular to the base, when the liquid stands on that line, the flat side is perpendicular or plumb. Intervening angles are marked, and, with the aid of simple [[conversion tables]], the instrument indicates the rate of fall per set distance of horizontal measurement, and set distance of the sloping line. cj rocks tandon sucks....
 
  
−
==Accuracy==
+
Note that since multiplication is [[distributive]] it is equally valid to add the tangents of the angles and ''then'' multiply them by D:
−
[[File:Vickers Clino R.JPG|thumb|Clinometer designed to enable [[indirect fire]] capability with a [[Vickers machine gun]] circa 1918]]
 
−
Certain highly sensitive electronic inclinometer sensors can achieve an output resolution to 0.001 degrees - depending on the technology and angle range, it may be limited to 0.01º. An inclinometer sensor's true or absolute accuracy (which is the combined total error), however, is a combination of initial sets of sensor zero offset and sensitivity, sensor linearity, hysteresis, repeatability, and the temperature drifts of zero and sensitivity - electronic inclinometers accuracy can typically range from .01º to ±2º depending on the sensor and situation. Typically in room ambient conditions the accuracy is limited to the sensor linearity specification.
 
  
−
[[Image:Well's Clinometer - Project Gutenberg eText 19465.png|thumb|The Well's clinometer]]
+
:''A'' = tan ''a''
−
[[Image:Clinometerlow.jpg|thumb|A simple clinometer]]
+
:''B'' = tan ''b''
 +
:''H'' = (''A'' &times; ''D'') + (''B'' &times; ''D'') = (''A'' + B) &times; ''D''
  
−
==Sensor technology==
+
Note also that both angles should be [[positive number]]s (i.e. ignore any [[minus sign]] on the clinometer's scale).
 +
done by: frank bonitto
  
−
[[Tilt sensor]]s and inclinometers generate an [[artificial horizon]] and measure angular tilt with respect to this horizon. They are used in cameras, aircraft flight controls, automobile security systems, and speciality switches and are also used for platform leveling, boom angle indication, indeed anywhere tilt requires measuring.
+
==Units of measure==
 +
There are typically three different units of measure that can be marked on a clinometer: [[degree (angle)|degrees]], [[percent]], and topo. When buying a clinometer it is important to make sure it is calibrated to units suitable for the intended use.
  
−
Important specifications to consider when searching for tilt sensors and inclinometers are the tilt angle range and number of axes (which are usually, but not always, [[orthogonal]]). The tilt angle range is the range of desired linear output. <!-- doesn't matter what it's measured in, and last sentence just repeats the back end of the first -->
+
==Tree height measurement==
 +
[[Image:Illustration of the basic trigonometric principles used by a clinometer.JPG|right|200px|thumb|Tree height measurement]]
 +
The [[forester]] stands at a fixed distance from the base of the [[tree]]. The most common distances in the [[United States]] are {{convert|50|ft|2}}, {{convert|66|ft|2}}, and {{convert|100|ft|2}}.<ref> Avery, T.E. and Burkhart, H.E. “Height Measurement Principles.” Forest Measurements 5th Edition. McGraw-Hill, 2002. 154.</ref> To obtain accurate readings it is best to use taped measured distance instead of [[Pacing (forestry)|paced distances]]. For the most accurate readings it is best to use a distance that is not less than the height of the tree being measured.<ref> Williams, M.S., Bechtold, M.A., and V.J. LaBau. 1994 five instruments for measuring tree heights: an evaluation. Southern Journal of Applied Forestry 18: 76-82</ref>, that is, that the clinometer will measure an angle less than 45° (100%).
  
−
Common sensor technologies for tilt sensors and inclinometers are accelerometer, [[Liquid Capacitive Basics |Liquid Capacitive]], electrolytic, gas bubble in liquid, and pendulum.
+
The observer sights to the top of tree, if total height is the desired measurement. If the desired measurement is merchantable height &ndash; that is, the height producing timber that can be sold &ndash; the observer sights to a point on the tree above which no more merchantable timber is found. The observer then measures to the bottom of the tree, takes the tangents and multiples them by the distance, and adds the two figures together. This will be the height of the tree.
  
−
Tilt sensor technology has also been implemented in video games. ''[[Yoshi's Universal Gravitation]]'' and ''[[Kirby Tilt 'n' Tumble]]'' are both built around a tilt sensor mechanism, which is built into the cartridge. The [[PlayStation 3]] and [[Wii]] game controllers also use tilt as a means to play video games.
+
The observer must always measure a leaning tree so that the tree is leaning to the left or right. Measurements should never be taken with the tree leaning toward or away from the observer because this will affect their [[accuracy]] because of [[foreshortening]].
  
−
Inclinometers are also used in [[civil engineering]], for example to measure the inclination of land to be built upon.
+
==Slope measurement==
 +
[[Image:Measuring Slope With a Clinometer 2.JPG|right|200px|thumb|Measuring slope with a clinometer]]
 +
The clinometer is also commonly used by foresters to obtain the [[gradient|percent slope]] of terrain. This measurement is based on the same trigonometric principles described above. Slope measurements, however, require that both observer and target be a constant height above the ground; thus a range pole or height of measurement (HI) stick is often used in slope measurements.
 +
{{commonscat}}
 +
==Manufacturers==
 +
* [[Brunton, Inc.]]
 +
* [[Suunto]]
 +
* [[Haglöf]]
 +
* [[Silva compass]]
  
−
==Uses==
+
==See also==
 +
*[[Inclinometer]]
  
−
Inclinometers are used for:
 
−
* Determining latitude using [[Polaris]] (in the Northern Hemisphere) or the two stars of the constellation [[Crux]] (in the Southern Hemisphere).
 
−
* Determining the angle of the earth's magnetic field with respect to the horizontal plane.
 
−
* Showing a deviation from the true vertical or horizontal.
 
−
* [[Surveying]], to measure an angle of inclination or elevation.
 
−
* Alerting an equipment operator that it may tip over.[http://www.riekerinc.com/TiltIndicators.htm]
 
−
* Measuring angles of elevation, slope, or incline, e.g. of an embankment.
 
−
* Measuring slight differences in slopes, particularly for [[geophysics]]. Such inclinometers are, for instance, used for monitoring [[volcano]]es, or for measuring the depth and rate of landslide movement.
 
−
* Measuring movements in walls or the ground in civil engineering projects.[http://www.slopeindicator.com/instruments/inclin-intro.html]
 
−
* Determining the dip of beds or strata, or the slope of an embankment or cutting; a kind of plumb level.
 
−
* Some automotive [[safety]] systems.
 
−
* Indicating pitch and roll of vehicles, nautical craft, and aircraft. See [[turn coordinator]] and [[slip indicator]].[http://www.riekerinc.com/SlipIndicators.htm]
 
−
* Monitoring the boom angle of cranes and material handlers.
 
−
* Measuring the "look angle" of a satellite antenna towards a satellite.
 
−
* Measuring the slope angle of a tape or chain during distance measurement.
 
−
* Measuring the height of a building, tree, or other feature using a vertical angle and a distance (determined by taping or pacing), using [[trigonometry]].
 
−
* Measuring the angle of drilling in [[well logging]].
 
−
* Measuring the [[List (watercraft)|list]] of a [[ship]] in still water and the roll in rough water.
 
−
* Measuring steepness of a [[ski slope]].
 
−
* Measuring the orientation of [[plane (mathematics)|plane]]s and [[lineation]]s in rocks, in combination with a [[compass]], in [[structural geology]].
 
−
* Measuring [[Range of Motion]] in the joints of the body
 
−
* Measuring the angles of elevation to, and ultimately computing the altitudes of, many things otherwise inaccessible for direct measurement. <!-- POV: This is especially useful in a classroom setting with children who will learn a valuable skill that applies directly to many careers. -->
 
  
−
== See also ==
+
==References==
−
* [[Theodolite]]
+
{{Reflist}}
−
* [[Clinometer (forestry)]]
 
  
−
== External links ==
 
−
*[http://www.inclinometer.blogspot.com Inclinometer Blog - General Inclinometer Information]
 
  
−
[[Category:Surveying instruments]]
+
[[Category:Forest modelling]]
 
[[Category:Dimensional instruments]]
 
[[Category:Dimensional instruments]]
−
[[Category:Inclinometers]]
 
−
 
−
[[ar:مميال]]
 
−
[[de:Neigungsmesser]]
 
−
[[es:Clinómetro]]
 
−
[[fr:Inclinomètre]]
 
−
[[hi:नतिमापी]]
 
−
[[it:Clinometro]]
 
−
[[ja:クリノメーター]]
 
−
[[no:Klinometer]]
 
−
[[pl:Inklinometr]]
 
−
[[pt:Inclinômetro]]
 
−
[[ru:Инклинометр]]
 
−
[[sl:Klinometer]]
 
−
[[sv:Inklinometer]]
 

Revision as of 21:45, 25 April 2010

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.

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.&

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). done by: frank bonitto

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.

Tree height measurement

File:Illustration of the basic trigonometric principles used by a clinometer.JPG
Tree height measurement

The forester stands at a fixed distance from the base of the tree. The most common distances in the United States are Template:Convert, Template:Convert, and Template:Convert.& To obtain accurate readings it is best to use taped measured distance instead of paced distances. For the most accurate readings it is best to use a distance that is not less than the height of the tree being measured.&, that is, that the clinometer will measure an angle less than 45° (100%).

The observer sights to the top of tree, if total height is the desired measurement. If the desired measurement is merchantable height – that is, the height producing timber that can be sold – the observer sights to a point on the tree above which no more merchantable timber is found. The observer then measures to the bottom of the tree, takes the tangents and multiples them by the distance, and adds the two figures together. This will be the height of the tree.

The observer must always measure a leaning tree so that the tree is leaning to the left or right. Measurements should never be taken with the tree leaning toward or away from the observer because this will affect their accuracy because of foreshortening.

Slope measurement

File:Measuring Slope With a Clinometer 2.JPG
Measuring slope with a clinometer

The clinometer is also commonly used by foresters to obtain the percent slope of terrain. This measurement is based on the same trigonometric principles described above. Slope measurements, however, require that both observer and target be a constant height above the ground; thus a range pole or height of measurement (HI) stick is often used in slope measurements. Template:Commonscat

Manufacturers

See also


References

  1. ↑ Calvert, J.B. “The Clinometer.” 2003.
  2. ↑ Avery, T.E. and Burkhart, H.E. “Height Measurement Principles.” Forest Measurements 5th Edition. McGraw-Hill, 2002. 154.
  3. ↑ Williams, M.S., Bechtold, M.A., and V.J. LaBau. 1994 five instruments for measuring tree heights: an evaluation. Southern Journal of Applied Forestry 18: 76-82
Retrieved from "https://wiki.pathfindersonline.org/index.php?title=AY_Honors/Forestry/Answer_Key&oldid=41332"