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Session 51 : Area measurement, pacing, compass use
Total time 3 hours
Goals
- For the trainees to learn how to measure an area,
- For the trainees to learn how to pace,
- For the trainees to learn how to use a compass,
- For the trainees to calculate an area's dimensions.
Overview
In this session, the trainees learn about land measurements, methods of measuring, instruments to use in measuring and how to calculate the area measured.
Exercises
1. Pacing
2. Compass
3. Simple Traverse
4. Simple Calculations
Exercise 1 Pacing
Total time 30 minutes
Objective
- To teach the trainees how to measure distance by pacing.
Overview
Pacing, if done correctly, can be used to get good distance measurements. The technical trainer instructs the trainees in the method of pacing and how to measure distance by pacing.
Procedures
Activities
1. The technical trainer lectures on pacing and gives instructions in the use of a pacing stick (lecture follows, post on newsprint).
Time
15 minutes
Activities
2. The trainees determine their pace and make a pacing stick for themselves.
Time
15 minutes
Pacing
Pacing, if done correctly, can be used to get good distance measurements.
Methods for developing pacing skills:
1. Lay out a base line 20 meters long,
2. Walk naturally along base line to determine how many paces you take for 20 meters (1 pace = 2 steps),
Figure 34
3. Cut a stick the length of your pace,
4. On flat ground you can pace naturally keeping track of every 20 meter interval,
5. On slopes you can use your stick to measure your horizontal pace.
Figure 35
Pacing Examples
1. My paces 2 steps = 1.6 meters, (My stick is 1.6 meters long),
My pace for the 20 meter baseline = 12.5 paces,
62.5 paces = 100 meters.
2. When actually pacing an unknown distance, put out a finger, or pick up a stone or stick to keep track of every 20 meter segment. Total distance can easily be calculated in your head.
You have the man move up or down the slope until you see the mark through the sight. He puts a stake in that spot, and then moves to the next mark. Fairly soon, you will have stakes all along the contour of the slope for that particular terrace.
Figure 36
Figure 37
All of these points are ten meters apart. You want to make an average line from these points (stake markers) since a jaggered line would be difficult with which to work. Further, puddles of water would gather in the pockets.
Example: At the end of an unknown segment, I have 3 stones in my hand and 4 paces more.
3 X 20 meters = 60 meters
4 X 1.6 approx. equals 4 X 1.5 = 6 meters
Total Distance = 66 meters
Trainer's Note: Although pacing is not widely used in the U.S., it is desirable for PCVs to know this method for use in developing countries and to be able to teach the same.
Exercise 2 Compass
Total time 30 minutes
Overview
Some of the participants will not have been instructed in the use of a compass. Those who know how to use a compass will assist other trainees in learning to use it.
Procedures
Activities
1. The trainer lectures on the use of a compass. On newsprint, show the Azimuth compass, Quadrant compass and the European compass and their use.
Time
15 minutes
Activities
2. The trainees who do not know how to use compasses practice aided by the trainees who know how to use them.
Time
15 minutes
Figure 38 : European compass
Figure 39 : Using the Compass
Figure 40 : Azimuth compass
Figure 41 : Quadrant compass
Figure 42 : Compass declination
Exercise 3 Simple Traverse
Total time 1 hour
Overview
This exercise gives the trainees a chance to use pacing skills and a compass to run a simple traverse.
Procedures
Activities
1. Prior to this session, the technical trainer stakes an area on which the trainees practice. The technical trainer uses flags to mark points. The area selected should have some steep slopes.
Activities
2. The trainees are divided into groups with at least one forester trainee in each group.
Activities
3. The trainees run a traverse using a hand compass and pacing.
Time
30 minutes
Activities
4. Upon completion of traverse, the trainees plot the area on graph paper and calculate the area.
Time
30 minutes
Figure 43
Exercise 4 Simple Calculations
Total time 1 hour
Overview
In this session, the trainees learn a simple method of determining approximate land areas.
Procedures
Activities
1. The technical trainer lectures on area calculations and posts the following on newsprint.
A. Plot a traverse to scale on sheet,
B. Break down the traversed figure into right triangles and/or rectangles,
C. Calculate each area in right triangle and/or rectangle,
D. Divide by 10,000 to get hectares,
Area Formulae
Area of right triangle = 1/2 (base) (height)
Area of rectangle = (base) (height)
(can check by counting squares on graph paper).
Activities
2. The technical trainer continues with lecture on area traverse record keeping. Displays the following example.
Figure 44 : Example of calculating area by breaking area figure into right triangles
Area Traverse
Keeping records - what, again? Field book traverse records
Field Sketch Figure 45) :
|
Sta |
Dist |
Bearing |
|
1 |
580°E (100°) |
|
|
B.S. N80° (265°) |
||
|
401 |
||
|
2 |
585°W |
|
|
B.S. N86°E (265°) |
||
|
326 |
||
|
3 |
N 10°E |
|
|
B.S. S11°W (10°) |
||
|
189 |
||
|
1 |
Hypothetical Data Sheet
Date: November 18, 1981
Weather: Clear
Crew: Mohammed Bah Peter, PCV Flomo Garteh
Tools: Hand. Compass & Pacing stick
Figure 46
Activities
3. The technical trainer checks each group's area map, calculations and traverse.
Trainer’s Note: While the technical trainer works with one group at a time the other groups use a rustic transit. This gives everyone time to practice. This is also a time to observe how wolf forester trainees are able to transfer skills, explain, have patience, etc., with generalist trainees. Record these observations because you will want to give forester trainees feedback during the interview on their performance.