1. Instructional Materials Service Texas A&M University - 8987E -
Compass & Pacing
Instructional Materials Service
Texas A&M University
- 8987E -

2. Compass & Pacing Baseplate Compass Engineer’s Lensatic Compass Pacing
Compass Use

3. Baseplate Compass There are several grades and types of
compasses. A good baseplate compass will
have a:
Rotating, fluid-filled housing
Baseplate
Compass needle
North alignment needle
Direction-of-travel arrow

4. Baseplate Compass Scale Direction-of-travel arrow Magnifier
North alignment
Rotating housing
Compass needle
Orientation lines
Compass housing

5. Baseplate Compass Baseplate compasses may include: A scale A magnifier
Templates
Lanyard (a wrist, or neck travel cord)
Scale
Direction-of-travel arrow
Magnifier
Slot for lanyard

6. Baseplate Compass
The fluid-filled housing slows the motion of the needle so the operator does not need to hold the compass motionless during use.
Housing

7. Baseplate Compass
The compass housing includes degree marks, 0° to 360°.
The reading for North is both 0° and 360°.
Housing

8. Baseplate Compass
The red end of the compass needle always points to Magnetic North.
North alignment
Compass needle

9. Engineer‘s Lensatic Compass
Compass includes:
A fluid-filled housing
A Magnetic North arrow
Directional marks
A magnifying lens
A line-of-sight directional viewfinder

10. Pacing

11. Pacing Two methods of pacing: Pace equals two steps
Pace equals steps traveled in a 100-foot distance

12. Method 1:
Pace Equals Two Steps

13. Pace Equals Two Steps Determining an accurate pace:
Measure a 100-foot distance between two markers, Point A and Point B.
The area between the markers should be flat and free of obstacles.

14. Pace Equals Two Steps
Travel from Point A to Point B, counting off each step.
Repeat several times recording step count each time.

15. Pace Equals Two Steps
Divided total number of steps recorded (120) by number of attempts completed (3) (120) steps ÷ (3) attempts = 40 steps
Average equals (40) steps.

16. Pace Equals Two Steps
Divide (100) distance by (40) step average 100 ÷ 40 = (2.5) step length
Multiply (2.5) step length by (2).
2.5 x 2 = 5
Pace = 5 feet

17. Method 2:
Steps Traveled in 100 Feet

18. Steps Traveled in 100 Feet
Once an average pace is established, it is possible to determine how many steps it will take to travel a given distance.
In this example, 40 steps = 1 pace

19. Steps Traveled in 100 Feet
Distance from point A to point B = (160) steps
Pace = (40) steps
Divide (160) distance from A to B by (40) steps
160 ÷ 40 = 4
Multiply 4 by (100) distance used to find pace
4 x 100 = 400
Distance to target is 400 feet

20. Steps Traveled in 100 Feet Calculate the number steps to travel a
distance of 185 feet.
Divide (185) distance by 100
185 ÷ 100 = 1.85
Remember: 40 steps = 1 pace
Multiply 40 by 1.85
1.85 x 40 = 74
It will take 74 steps to travel 185 feet.

21. Pacing (Obstacles)
It is necessary to determine pace on uneven terrain, through ditches, grasses, trees, brush of various heights, and other obstacles.

22. Pacing Beginners should:
Use a measuring tape to accurately measure a 100-foot distance.
Practice on clean, level ground, using a natural walking gait.
Maintain a constant, reliable pace, regardless of the obstacles.

23. Compass Use

24. Compass Use
The Earth’s North and South poles act like a huge magnet. One pole is positive and one pole is negative.
Because magnetic and true North are not the same, corrections are made in surveying to compensate for this difference. The difference is referred to as magnetic declination.

25. Compass Use
The compass needle, which floats in the fluid-filled chamber, is magnetized.
Regardless of the compass position, the red needle is drawn to the Magnetic North Pole.

26. Compass Use
The circular rotating housing enclosing the needle is marked in degrees in increments from 0° to 360°.
Degrees are also referred to as the azimuth or bearing.
Housing

27. Compass Use
Directional letters N, S, E, and W, are identified on the housing.
North South East West

28. Compass Use
Example: To find the direction-of-travel based on a compass reading of 210 feet at 320° from a specific location:

29. Reading 210 feet at 320°
Rotate the housing on the compass until the 320° mark lines up with the direction-of-travel arrow.
Direction-of-travel arrow
320°

30. Reading 210 feet at 320°
Rotate the entire compass until the compass needle lines up in the North alignment position.
Direction-of-travel arrow
Needle in the North Alignment Position

31. Reading 210 feet at 320°
Holding the compass at eye level, use the direction-of-travel arrow to identify a distant landmark.
Walk in a straight line as indicated by the direction-of-travel arrow for a distance of 210 feet to the recorded location.

32. Compass Reading 210 feet at 320°

33. Compass Use
Note: All magnetic objects, such as belts, watches, keys, and other metal objects can interfere with the compass reading.
Hold compass away form metal objects when taking a reading.

34. Compass Use
Aerial maps are available through the Natural Resource Conservation Service or the Soil and Water Conservation District.
Maps should be read with a compass on a flat, horizontal surface, away from metal objects.
Readings may be taken from maps based on specific location and the direction to be traveled.

35. Compass Use
The ability to use a compass effectively is an essential skill for wildlife managers, biologists, and other scientists who work outdoors. It is also a beneficial tool for the outdoor enthusiast.

36. Acknowledgements
Dr. Joe Dettling, Associate Professor, Instructional Materials Service, Texas A&M University, researched and developed the information used in this PowerPoint Presentation.
Jerry Dornak, Agricultural Science & Technology Instructor, Goliad High School, Goliad, Texas and Dr. Terry Blankenship, Wildlife Biologist, Welder Wildlife Foundation, Sinton, Texas, reviewed material used this PowerPoint.
Christine Stetter, Artist, Instructional Materials Service, Texas A&M University, developed and illustrated this PowerPoint Presentation.
Vickie Marriott, Office Associate, Instructional Materials Service, Texas A&M University, edited the material in this PowerPoint Presentation.