ONTAP - Map and Compass

1. Introduction to Map
and Compass
SHSM Certificate

2. Introduction to Map
and Compass
This tutorial consists of four parts. The objective is to
provide you with a basic understanding of the map and
compass as used for navigation on land. There is a
short quiz at the end of each part.
Part 1: Globe to Map – Round to Flat
Part 2: Topographic Maps
Part 3: The Magnetic Compass
Part 4: Navigation

3. Introduction to Map
and Compass
Part 1: Globe to Map –
Round to Flat

4. Our planet is generally spherical.
Maps are flat.
Have you ever tried to remove an
orange peel in one piece? What
happens if you try to flatten it?
You end up with large gaps and
tears. That’s what happens when
you try to make a flat map of a
round earth….the process is
called PROJECTION.
Globe to Map – Round to Flat
Projection

5. There are dozens of different
PROJECTIONS that try to solve
the problems of going from round
to flat.
All maps are distorted in some
aspect. Four things that become
distorted are: area, shape,
direction, and distance.
Globe to Map – Round to Flat
Projection

6. If you place a light source inside a
transparent globe, and mark where
areas of land appear on a flat
screen, you are PROJECTING
In reality, this is done
mathematically rather than using
light and screens, but the principles
are the same.
Notice how things at the centre are
much less distorted than things at
the edges.
This is a major problem for
navigation!
Globe to Map – Round to Flat
Projection

7. Notice how the size and area
of Greenland are distorted in
this PROJECTION.
But notice how the shape is
very similar to the globe.
What we need for navigation on land is a map
that will preserve shapes, distances and
directions…
Globe to Map – Round to Flat
Projection

8. Imagine that you could wrap a
sheet of paper around the earth.
If you think about it, the paper is
only touching the surface along a
single line.
That line becomes the CENTRAL
MERIDIAN of your map.
Everything touching that line can
be accurately transferred to the
paper.
The farther you move away from
the line, the more distorted things
get.
Globe to Map – Round to Flat
Projection

9. 6° of longitude
Stops at ~80°South Latitude
Stops at ~80°North Latitude
Central Meridian
This method gives you a map that is accurate to about 3° east and west
of the CENTRAL MERIDIAN, making it about 6° of longitude wide.
Globe to Map – Round to Flat
Projection

10. By using a series of meridians 6° apart, it is possible to project an
accurate map of the entire surface of the earth.
Globe to Map – Round to Flat
Projection

11. Maps are named for the projection technique used. These maps
are therefore known as UNIVERSAL TRANSVERSE
MERCATOR or “UTM” maps.
There are 60 UTM zones, each 6° wide…
adding up to…360°…get it? Each numbered zone is broken into
smaller parts identified by letters…we happen to be in Zone 17T
Globe to Map – Round to Flat
Projection

12. Equator
A rectangular grid is overlaid on
the maps in order to provide
accurate location information.
You will learn to use this later in
the lesson.
The map’s actual ORIGIN
(starting point) is where the
Equator and the
CENTRAL MERIDIAN meet.
But…
Central
Meridian
Map
Origin
Globe to Map – Round to Flat
Projection

13. Equator
“False”
Origin
To make the numbering system
make more sense,
it actually begins at the
FALSE ORIGIN.
Notice that the blue grid does not
align perfectly with the lines of
longitude. You’ll learn more about
“North” later.
Central
Meridian
Map
Origin
Globe to Map – Round to Flat
Projection

14. Map makers simplify the real world
to make maps easier to read.
They decide what gets left out and
what gets added, depending on the
map and its intended use.
Reality is way too detailed to
include it all!
Globe to Map – Round to Flat
Generalization and Simplification

15. Rivers can be
reduced to a line.
Individual trees
become areas of
green.
Roads can be thicker
than they really are
and the curves are
simplified.
Globe to Map – Round to Flat
Generalization and Simplification

16. Notice how large buildings become simple black outlines. Also notice
that not all buildings are shown.
One reason for this
is to simplify the map.
Another is that buildings
may have ben built since
the map was created.
The world changes, the map does not!
That’s why you should always check the date of publication of a map
you are using!
Globe to Map – Round to Flat
Generalization and Simplification

17. More examples of GENERALIZATION.
Notice that although a large amount of detail is left off of
the map, it still provides a very accurate idea about the land it shows.
Globe to Map – Round to Flat
Generalization and Simplification

18. Com
352.4
Buildings
(Small buildings are less detailed)
School
Church
Communication Tower
(Usually easy to spot due to height)
Tank or Silo
Benchmark with
Elevation
(Surveyed point with known elevation)
Globe to Map – Round to Flat
Common Symbols You Should Know

19. Track
(a foot path)
Road-Loose Surface
(a gravel road)
Road-Hard Surface
(a paved road)
Bridge
(can be highway or railway)
Single Track Railway
Transmission Lines
(steel towers or poles)
Globe to Map – Round to Flat
Common Symbols You Should Know

20. River/Stream
Pond/Lake
Intermittent Pond/Lake
(it may or may not be there…
depends on the season.)
Swamp/Marsh
Built up Area
(village/town/city)
Orchard
Wooded Area
Globe to Map – Round to Flat
Common Symbols You Should Know

21. Introduction to Map
and Compass
End of Part 1
Do QUIZ 1 now.

22. Introduction to Map
and Compass
Part 2: Topographic Maps

23. Datum Conversions
The “Norths”
Index to Adjoining
Maps
Map Name
UTM Zone
Contour Interval and
Map Datum
Scales
Topographic Maps
The map most frequently used for land navigation in Canada
is the 1:50,000 scale UTM map produced by
Natural Resources Canada (NRCan).
Its main
features are
labeled in this
diagram.
You will learn
about each of
them in the next
set of slides.
UTM Grid

24. This is the way that NORTH is shown on
Canadian topographic maps.
It displays TRUE NORTH , MAGNETIC
NORTH and a third North.
Recall that that the blue grid does
not align perfectly with the lines
of longitude.
This is where we get the third “North”, known
as GRID NORTH.
When using these maps, it is best to navigate
using GRID NORTH.
Topographic Maps
The “Norths”

25. Topographic Maps
UTM Zone
It is important to know what UTM Zone you are working in,
especially if you are also using GPS to assist in your
navigation.
This map is found in Zone 17T.

26. Topographic Maps
Map Name
Canadian topographic maps are
generally named for the major
feature (natural or man made)
near the centre of the map sheet.
This does not mean that the entire
feature will appear on the map;
you may need to acquire adjoining
sheets.
On this map, the city of
Cambridge, Ontario is found near
the centre of the map.

27. On the right side of the
map you will find the
“Index to adjoining Maps
of the National
Topographic System”
Its pretty simple. The map
you have is the one in the
centre (40 P/8).
If you want to travel to
Brantford, you need to get
the map sheet to the south
(40 P/1)
Topographic Maps
Map Index

28. Topographic Maps
Map Datum
Actual shape of earth
Contrary to what you may have been taught, the earth is not a
sphere. Its actually more pear shaped…and its lumpy.

29. Topographic Maps
Map Datum
North American Datum 1927 (Green)
Actual shape of earth
To make maps fit together, cartographers use a DATUM as a
common reference.
The DATUM is a “smoothed out” version of the real earth.
DATUMS are named according to date or location of origin.
North American Datum is usually
written as NAD. The number after it
is the year…so…NAD27

30. Topographic Maps
Map Datum
North American Datum 1927 (Green)
North American Datum 1983 (Red)
Actual shape of earth
But…a DATUM can change as new technology appears and
makes them more accurate.
You should be aware of the DATUM that was used to create
the map you are navigating with.
NAD27
NAD83

31. Topographic Maps
Map Datum
The DATUM is listed
along the bottom of the
map, usually along with
the information about
CONTOUR INTERVAL
This map was created
using the North
American Datum 1983
or NAD83

32. Topographic Maps
Datum Conversions
Earlier maps in this series were
produced using NAD27.
Now they are all NAD83, BUT…
there are still a lot of sources using
older maps.
Since the DATUM changes the shape, some things are
displaced on the two versions of the same map.
The DATUM CONVERSION chart tells you how much
difference there is, and how to make adjustments.
This is usually not a problem when using a compass, but
if you also use GPS it is CRITICAL to use the correct
DATUM.

33. Topographic Maps
Contours
One of the most valuable aspects of the TOPOGRAPHIC MAP is its
ability to convey information about the shape of the land.
It shows the shape by using CONTOURS
You may recall from Grade 9 Geography that a CONTOUR is a line that
joins points with the same elevation.
If you walk ALONG a CONTOUR LINE you stay at the same elevation.
If you walk ACROSS a CONTOUR LINE you either go up or down.
In the next few slides you will learn to tell the difference!

34. Topographic Maps
Contours
Imagine that we are
looking at a small hill,
from the side.
We also know what it
looks like from above.

35. 210 m asl
200 m asl
190 m asl
180 m asl
170 m asl
160 m asl
150 m asl
Topographic Maps
Contours
Now we divide the hill
into horizontal slices.
In this case each slice
is 10 m thick.
They are assigned
heights ABOVE SEA
LEVEL or asl
The base of this hill is
150m asl. The peak
is just over 200 m asl.
Every point on this
line is 150m asl

36. 210 m asl
200 m asl
190 m asl
180 m asl
170 m asl
160 m asl
150 m asl
Topographic Maps
Contours
The elevations are
transferred to the map
and CONTOUR
LINES are produced
for every 10 m change
in elevation.
Every point on this
line is 160m asl

37. 210 m asl
200 m asl
190 m asl
180 m asl
170 m asl
160 m asl
150 m asl
Topographic Maps
Contours
The result is a familiar
set of nested lines that
show the shape of the
hill.

38. 100
150
To make it easier to follow
complex CONTOUR
LINES, every fifth line is
bolded and has its value
printed along it. These are
called INDEX CONTOURS.
Topographic Maps
Contours

39. 100
150
The closer the CONTOUR
LINES are, the steeper the
slope is.
The path to “B” is less steep
than the path to “A”.
Topographic Maps
Contours
B
A

40. AA
BB
In order to find the
STRAIGHT LINE
distance from “A” to “B”
you will need a pencil
and a piece of paper.
Topographic Maps
Determining Straight Line Distance

41. AA
BB
Put the edge of the paper
over the map so that it
passes through both
points.
Mark the two points on
the paper.
Topographic Maps
Determining Straight Line Distance

42. AA
BB
Put the paper along the
appropriate scale on the
map and determine the
distance between the
marks.
In this example, 1km (to
the right of the “0”) and
700 m to the left, for a
total of 1700 m.
Topographic Maps
Determining Straight Line Distance

43. AA
BB
Finding distances along curves
is more complicated, but still
easy.
Put the edge of the paper over
the map so that it aligns with
the first segment of the road.
Mark the start point on the
paper.
Topographic Maps
Determining Distance Along a Curve

44. AA
BB
Now mark the furthest
point along the edge
where it still touches the
road.
Keep the pencil point
pressed against the page
and rotate the paper
around it…
Topographic Maps
Determining Distance Along a Curve

45. AA
BB
Mark the next point, then
repeat the procedure.
Topographic Maps
Determining Distance Along a Curve

46. AA
BB
Keep going, turning the
paper to align with the
road, marking each point
as you go.
Topographic Maps
Determining Distance Along a Curve

47. AA
BB
…and again…
Topographic Maps
Determining Distance Along a Curve

48. AA
BB
…and again…
Topographic Maps
Determining Distance Along a Curve

49. AA
BB
…and again…
Topographic Maps
Determining Distance Along a Curve

50. AA
BB
…and again.
Topographic Maps
Determining Distance Along a Curve

51. AA
BB
Put the paper along the
appropriate scale on the
map and determine the
distance between the
marks.
In this example, 1km (to
the right of the “0”) and
900 m to the left, for a
total of 1900 m.
.
Startpoint
Endpoint
Topographic Maps
Determining Distance Along a Curve

52. AA
BB
Another way is to use a piece
of string or soft wire.
Start with one end at “A”.
Make sure it follows the raid as
closely as possible.
Use your finger to mark the
end at “B”.
Topographic Maps
Determining Distance Along a Curve

53. AA
BB
Move the string to the
scale, pull it straight and
read the distance.
In this case it is almost
exactly 1900m.
Topographic Maps
Determining Distance Along a Curve

54. The UTM Grid squares are
1000m x 1000m (regardless of
map scale)
They can be used as a quick
method of estimating distance
on the map.
Also, for those who are
mathematically inclined, on a
1:50,000 scale map, 1cm =
500m. You can use a ruler to
measure distances, but be
careful…its easy to make
mistakes.
Topographic Maps
Other Methods of Determining Distance

55. Topographic Maps
Determining Location-UTM Grid
Look closely at the map
and you will notice a
series of blue GRID
LINES forming squares.
Without the map in the
way, they look like this.
04
03
42 43
The squares are 1000m on each side…which could be
why its known as a “thousand meter grid”!

56. The numbers along the bottom tell
you how far EAST you are of the
map’s FALSE ORIGIN (remember
that ?) The number is called an
EASTING.
The numbers along the side tell you
how far NORTH you are of the
map’s FALSE ORIGIN. The number
is called a NORTHING.
04
03
42 43
You ALWAYS find the EASTING and then the NORTHING.
Think of going into a house…in the door, up the stairs,,,you
can’t go up the stairs first!
NORTHING
EASTING
Topographic Maps
Determining Location-UTM Grid

57. Using the four numbers
provided by the EASTING
and NORTHING you can
find a general location
(GRID REFERENCE)
Remember, the square will
be 1 km x 1 km!
A GRID REFERENCE
always refers to the lower
left corner of the box.
Topographic Maps
Determining Location-UTM Grid

58. Then find the NORTHING…
42
03
First find the EASTING…
Topographic Maps
Determining Location-UTM Grid

59. 42
03
4203describes the
location of the lower left
hand corner of the grid
square containing the “Y”
intersection.
(Remember…in the door, up
the stairs.)
Topographic Maps
Determining Location-UTM Grid

60. 42
03
A four figure GRID
REFERENCE locates
objects inside a 1km x 1km
box. Normally more
precision is needed.
To do this you can subdivide
the box into smaller units.
You can “eyeball it” or use a
device called a ROMER.
A ROMER is a transparent
grid that fits over the grid on
the map and breaks the “big
square” into 100 smaller
squares.
Topographic Maps
Determining Location-UTM Grid

61. A six figure GRID
REFERENCE puts you
inside a 100 m x 100 m box,
which is generally good
enough for land navigation.
To determine a six figure
GRID REFERENCE lay the
ROMER over the square
you are interested in.
Topographic Maps
Determining Location-UTM Grid

62. Use the same EASTING that
you did for the four figure
GRID REFERENCE.
Add a third digit to describe
how many 100m squares you
are from the EASTING (in this
case 3).
The 42of the four figure
GRID REFERENCE becomes
423 in the six figure GRID
REFERENCE 423
Topographic Maps
Determining Location-UTM Grid

63. 42
03
3
6
Repeat the process for
the NORTHING.
Putting the two together
you get:
Notice that there are no
spaces, nor punctuation
or symbols of any kind.
Simply six digits!
423036
Topographic Maps
Determining Location-UTM Grid

64. To make navigation even
more accurate, subdivide each
square on the ROMER into
10 smaller units…you will get
an 8 DIGIT GRID
REFERENCE.
For example, the building just
North of the “Y” intersection is
located at:
42
03
3
6
42380365
Topographic Maps
Determining Location-UTM Grid

65. Topographic Maps
Determining Location-UTM Grid
4 Figure GRID REFERENCE = 1000m box good for general location
6 Figure GRID REFERENCE = 100m box good for specific area
8 Figure GRID REFERENCE = 10m box good for specific object
12 Figure GRID REFERENCE = 1m box provided by GPS

66. Introduction to Map
and Compass
End of Part 2
Do QUIZ 2 now.

67. Introduction to Map
and Compass
Part 3: The Compass

68. Baseplate
Needle
Scales
Orientation Lines
Index Arrow
Bearing Ring
Orienting Arrow
Magnetic Compass
Parts of the Compass

69. Magnetic Compass
Precautions
Things to check before you use a COMPASS:
•The NEEDLE should rotate freely
•If the case is liquid filled, check it for leaks
and cracks
•The BEARING RING should turn freely but
not be loose
•Be sure the COMPASS is marked in
degrees…some use MILS instead.

70. Magnetic Compass
Setting a Bearing
Turn the BEARING RING until the
ORIENTING ARROW lines up with the
desired BEARING.
In this case, 130° has been set.
Bearing Ring
Index Arrow

71. The earth rotates on its axis once
every day.
The geographic axis passes
through TRUE NORTH (and TRUE
SOUTH).
Longitude and latitude, as well as
the UTM co-ordinate system, are
based upon TRUE NORTH.
Your compass is NOT!
The compass uses magnetic
bearings.
Magnetic Compass
Earth’s Magnetism
T.N.

72. The earth’s magnetic field does not
pass through the geographic poles.
Not only that, but it moves!
Each year the magnetic pole
shifts slightly, which means
you must make adjustments
when navigating using a
magnetic compass.
The difference between TRUE
NORTH and MAGNETIC NORTH
is called DECLINATION (or
variation)
Magnetic Compass
Earth’s Magnetism
T.N.
M.N.

73. The difference between TRUE
NORTH and MAGNETIC NORTH
can be shown on a map.
The green line shows the points
where TRUE NORTH and
MAGNETIC NORTH actually line
up…there is zero variation.
The red lines are areas of easterly
variation, and the blue lines are
areas of westerly variation.
Magnetic Compass
Earth’s Magnetism

74. The difference between MAGNETIC
NORTH and TRUE NORTH (and GRID
NORTH) is called DECLINATION (or
variation).
Since the magnetic pole moves (more on
that later) the DECLINATION changes
constantly. The diagram provides all the
information you need to determine its
current value.
Magnetic Compass
The “Norths”

75. Instead of having to convert GRID
bearings (based on the map’s grid) to
TRUE and then TRUE to MAGNETIC
to use on your compass, you are
provided with the total
“APPROXIMATE MEAN
DECLINATION”
This will allow you to convert directly
from GRID to MAGNETIC bearings.
From now on in this presentation,
when BEARINGS are mentioned they
will be with respect to GRID NORTH.
Magnetic Compass
Finding North

76. What does this diagram tell you?
The DECLINATION was
10°02’ when the map
was printed.
The map was printed in 1998
DECLINATION is
increasing at 3.3’ per year
Magnetic Compass
Declination

77. The DECLINATION was
10°02’ when the map
was printed.
The map was printed in 1998
DECLINATION is
increasing at 3.3’ per year
Using this information, it is
simple to calculate today’s
declination.
For those of you looking at
this years from today,
assume it is still 2013!
So…
Step 1: 2013-1998=15years
Step 2: 15 x 3.3’=49.5’ (remember, there are 60’ in 1°)
Step 3: 10°02’ + 49.5’ = 10°51.5’ (You can take this as 11°)
But how important is this REALLY?
Magnetic Compass
Declination

78. Failing to account for DECLINATION
in this part of the world means that you
are off by 11°.
A simple calculation error (subtracting
instead of adding) could magnify that to
22°!
Do the math…that’s 440m
off track for every kilometer
you travel!
Do you really want to take a
chance and be that far off?
Magnetic Compass
Declination

79. 10° 10°
20° 20°
5°5°
West East
Adjusting Screw
Declination Scale
Higher quality compasses have an
adjustable base plate which allows
you to set DECLINATION.
A small adjusting screw allows you
to move the ORIENTING ARROW
to the proper setting.
Once it is set, you no longer need
to calculate declination.
Magnetic Compass
Declination
If your compass does not have this
feature you need to calculate and
adjust for DECLINATION every time
you set a bearing.

80. OKAY…confused? Take a look at
this example.
You want to travel North on your
map… GRID NORTH.
From where we stand in Kitchener,
MAGNETIC NORTH is presently
11° West of GRID NORTH.
If you follow a bearing of 0°, you will
go to MAGNETIC NORTH .
Magnetic Compass
Declination
Grid
North
Magnetic
North
Note: The offset of MAGNETIC NORTH
is exaggerated!

81. In order to get to GRID NORTH
you need to account for
DECLINATION (11° West ).
For DECLINATION to the West, you
need to ADD the value to the
BEARING you want to travel…in this
case 0° + 11°= 11°.
Set 11° under the INDEX ARROW.
Although the NEEDLE is pointing to
MAGNETIC NORTH, following the
11° BEARING will actually lead you
to the correct spot.
Magnetic Compass
Declination
Grid
North
Magnetic
North
Note: The offset of MAGNETIC NORTH
is exaggerated!

82. Magnetic Compass
Declination
Westerly DECLINATION is always added and
Easterly DECLINATION is always subtracted.
EASTERLY
DECLINATION
WESTERLY
DECLINATION
EAST IS LEAST, WEST IS BEST

83. Introduction to Map
and Compass
End of Part 3
Do QUIZ 3 now.

84. Introduction to Map
and Compass
Part 4: Navigation

85. In order to navigate, you need
to combine all of the
information you have been
shown, along with a couple of
other techniques.
In this section you will learn
how to:
•Take bearings from a map
•Take bearings from objects
•Follow a bearing
•Measure distance travelled
•Find your location
Remember…this is all
THEORY…there is no
substitute for practice!
Navigation
The Basics

86. Assume that you want to
travel cross country from the
intersection at “A” to the large
building at “B”
Navigation
Taking a Bearing From a Map

87. Lay the edge of the compass
on the map so that it aligns
with “A” and “B”.
Navigation
Taking a Bearing From a Map

88. Turn the BEARING RING
until the ORIENTATION
LINES align with the blue
grid lines on the map.
The position of the NEEDLE
does not matter at this point.
Read the bearing indicated
by the INDEX ARROW.
In this example, a bearing of
030° (grid) will get you from
“A” to “B”. But...
Navigation
Taking a Bearing From a Map

89. You need to account for
DECLINATION.
Adjust the BEARING for 11°
of Westerly DECLINATION.
31° + 11° = 41°
The BEARING to follow will
be 041° (magnetic).
Navigation
Taking a Bearing From a Map

90. Navigation
Orienting the Map
Look around you for objects that you
can recognize on the map.
In this case, a communication tower is
seen in the distance, as well as on the
map.
Turn the map so that the object is in
the same relative position as it is on
the ground.
It is best to keep the map oriented to
the ground as you navigate.

91. Aim across the top of the
compass at the object you
are taking the bearing to.
Align the centre of the
compass and the INDEX
ARROW with the object.
Navigation
Taking a Bearing From an Object

92. Turn the BEARING RING until the
ORIENTING ARROW lines up
with the RED end of the NEEDLE.
The BEARING can then be read
next to the INDEX ARROW. In
this case, 130° (magnetic)
Navigation
Taking a Bearing From an Object

93. Notice how the
ORIENTING ARROW
looks like a little shed?
When you are navigating, remember to
“KEEP RED IN THE SHED”
Incaseyoudon’tgetit…
theNorthendofthe
NEEDLEis“RED”
Navigation
Following a Bearing

94. Navigation
Following a Bearing
Set the desired BEARING on
the compass.
Aim across the top of the
compass, aligning the centre
of the NEEDLE with the
INDEX ARROW.
Find an object that is directly
on that line that you will be
able to keep in sight.
Walk to it! (We’ll discuss
distance next)

95. Navigation
Following a Bearing
What if there is no handy
object?
Have a friend walk out in
front of you while you while
you aim the compass.
Give them instructions to
keep them walking on the
desired track.

96. Navigation
Determining Distance
The compass will point you in the correct direction, but you also
need to know how to measure the distance you have covered.
The easiest way to do this is by counting paces.
Everybody’s pace is different, so you need to know yours!

97. Find a flat path that you can easily measure…a school track works
well. Measure off 100 metres.
Walk at a natural, comfortable pace, carrying what you will when
you hike (pack, water etc).
Count every time your right foot hits the ground. Do it several
times and take the average.
100 metres
Navigation
Determining Distance

98. Navigation
Determining Distance
Let’s say that you discover that you take 56 paces to cover 100m.
This means that every time your foot hits the ground for the 56th
time, you have covered 100m…as long as it is flat open ground!
56 paces
28 paces

99. Navigation
Determining Distance
You should find a place to try pacing up a hill…it will take more
paces! Also pace down the hill…you should take fewer. Also,
pacing in wooded areas is significantly different that open fields!
This requires practice, but with time you will learn how to accurately
measure your movement over various types of terrain.

100. Keeping track of how far you go is important.
“Ranger Beads” like these can help.
Each time you reach 100m, slide one
of the lower beads down.
When you reach 1000m, slide
one of the upper beads down
and slide the lower beads
back up.
Check the next
page for examples.
Each bead
represents
1km
Each bead
represents
100m
Navigation
Keeping Track of Distance

101. 100m
900m
1 km
Navigation
Keeping Track of Distance

102. Navigation
Triangulation
TRIANGULATION is a way
of locating yourself on the
map.
As the name implies, it is
based on three. In this case
bearings from three
recognizable features.
You can use towers,
buildings, road
intersections…practically
anything on the map that you
can see from your location.

103. Navigation
Triangulation
Assume that from where you
are standing, you can see a
communication tower and
two farm silos.
First, take a
compass bearing
to the tower.

104. Navigation
Triangulation
Remember to adjust for
DECLINATION!
To go from GRID to
MAGNETIC, you added 11°.
To go from MAGNETIC to
GRID, you have to subtract
the 11°

105. non-permanent
With the compass adjusted for
DECLINATION place it on the
map so that it touches the
object you took the BEARING
to (the tower!)
Now swing the COMPASS
until the ORIENTING LINES
line up with the GRID LINES.
Make sure the ORIENTING
ARROW points NORTH.
Ignore the NEEDLE.
Draw a line through the object
along the edge of the
COMPASS.
Navigation
Triangulation

106. Repeat the procedure for
using two more objects.
It is best to use objects that
are spaced out around you
(ie. At least 60° between
bearings).
You are located at the point
where the three lines
intersect.
Navigation
Triangulation

107. Navigation
Putting it all Together
Record the details of your planned trip on a ROUTE CARD
•Establish your route
•List the GRID REFERENCES
•Determine the BEARING
•Correct for DECLINATION
•Measure the DISTANCE
•Convert it to your PACES
•Make note of anything useful
along your path.

108. Things to keep in mind while navigating:
•Keep the COMPASS level so the NEEDLE can rotate
•Keep away from metal!
•Be aware of magnetic anomalies in the area you are
hiking (like large amounts of iron bearing rock!)
•Don’t constantly stare at the COMPASS while you
walk…you may be surprised what you trip over or fall
off of!
•Be aware of your general surroundings. For
example…in the morning the sun should be in the
EAST…not the WEST.
Navigation
Putting it all Together

109. Introduction to Map
and Compass
End of Part 4
Do QUIZ 4 now.