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UNITED STATES MARINE CORPS
FIELD MEDICAL TRAINING BATTALION
Camp Lejeune, NC 28542-0042
FMSO 212
Land Navigation
TERMINAL LEARNING OBJECTIVE
1. Given a military topographic map, protractor, and objective, navigate with a map and
compass to arrive within 100 meters of the objective. (HSS-MCCS-2014)
ENABLING LEARNING OBJECTIVES
1. Without the aid of reference, given a list, identify the information contained on a military
map, without any errors, per Map Reading and Land Navigation, FM 3-25.26. (HSS-MCCS-
2014a)
2. Without the aid of reference, given a list, identify the purpose of the 6 basic colors on a map,
without any errors, per Map Reading and Land Navigation, FM 3-25.26. (HSS-MCCS-2014b)
3. Without the aid of reference, given a list, identify the purpose of contour lines on a
military map, without any errors, per Map Reading and Land Navigation, FM 3-25.26. (HSS-
MCCS-2014c)
4. Without the aid of reference and given a list, identify the procedure for measuring distance on
a military map, with no discrepancies, per Map Reading and Land Navigation, FM 3-25.26.
(HSS-MCCS-2014d)
5. Without the aid of reference, given a military map, protractor, compass, and a set of 8 digit
grid coordinates, locate a position on a map, without omission, per Map Reading and Land
Navigation, FM 3-25.26. (HSS-MCCS-2014e)
6. Without the aid of reference, utilize a lensatic compass, per Map Reading and Land
Navigation, FM 3-25.26. (HSS-MCCS-2014f)
7. Without the aid of references, given a military map and a lensatic compass, orient the map to
the ground, without omission, per Map Reading and Land Navigation, FM 3-25.26. (HSS-
MCCS-2014g)
8. Without the aid of references, given a military map, lensatic compass, and a minimum of an 8
digit grid coordinate, locate specific points on a land navigation course, without omission, per
Map Reading and Land Navigation, FM 3-25.26. (HSS-MCCS-2014h)
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1. INFORMATION CONTAINED ON A MILITARY MAP
Purpose - the purpose of a map is to provide information on the existence, the location, and
the distance between ground features.
Definition - a geographic representation of the earth’s surface drawn to scale as seen from
above.
- Shows us what an area actually looks like without being there
- A clear and handy reference tool
Characteristics of a Map
- Designed to show us common information
- Location of ground objects
- Populated areas
- Routes of travel
- Communication Lines
- Extent of vegetation cover
- Elevation and relief of the earth's surface
Care and Importance
Maps are printed on paper and require protection from water, mud and tearing. When
you mark on your map, use lighter lines, which are easily erased, without smearing. If
trimming the map, be careful not to cut any of the marginal information. Maps must be
protected because they can hold tactical information, such as:
- Friendly positions
- Friendly supply points
Map Illustrations
Symbols
- The mapmaker uses standard symbols
- They represent natural and manmade features
- Resemble as closely as possible, the actual features but as viewed from above
Marginal Information - instructions that are placed around the outer edges of the map are
known as margin of information. All maps are not the same, so every time a different map is
used, you must examine the margin of information carefully:
Sheet Name - found in two places: The center of the upper margin and the lower right
margin
Contour Interval - appears in the center lower margin and states the vertical distance
between adjacent contour lines on the map
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Grid Box- The grid reference box is normally located in the center of the lower margin. It
contains instructions for composing a grid reference.
Declination Diagram - located in the lower margin and indicates the angular relationship of
true north, grid north and magnetic north (see figure 1):
Figure 1. Declination Diagram
- True North - a line from any position on the earth's surface connects at the North Pole.
Unlike grid lines, all lines of longitude are true north lines.
- Magnetic North - direction to the North Magnetic Pole, as indicated by the north-
seeking needle of a magnetic compass. The North Magnetic Pole is located in Canada
at Hudson Bay.
- Grid North - north that is established by the vertical grid lines on the map. The
variation between grid north and true north is due to the curvature of the earth.
Grid Magnetic (GM) Angle - the GM angle is an important factor in map reading. The GM
angle is used to convert magnetic azimuth to grid azimuth and vice versa:
Grid azimuth - determined with a protractor and is measured from grid north.
Magnetic azimuth - taken from a compass and measured from magnetic north.
Legend - located in the lower left margin. Illustrates and identifies some of the symbols on
the map. Every time a map is used, refer to the legend to prevent errors in symbol
identification (see figure 2). Other information found in the legend is the Sheet Name, Sheet
Number, Series Name, Edition Number, Index to Boundaries, Index Adjoining Sheets, and
Series Number.
Figure 2. Legend
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Bar Scale - located at the center bottom of the margin, below the map face. Special "rulers,”
ground distance may be measured directly without having to convert the map scale ratio.
Normally, the scale for meters, yards, statute miles (land) and nautical miles (sea). Easy to
use, but notice that "zero" is not at the end of the scale (see figure 3).
2. MAP COLORS - To ease the identification of features on the map, the topographic symbols
are usually printed in different colors, with each color identifying a class of features. The colors
vary with different types of maps, but on a standard, large scale, topographic map, there are five
basic colors.
Black - used to identify the majority of cultural or man-made features, such as
buildings, bridges, and roads not shown in red
Red - main roads, built up areas, and special features such as dangerous or restricted
areas
Blue - is for water features: lakes, rivers, swamps, and streams
Green - identifies vegetation such as woods and orchards
Red Brown - all landforms such as contours, fills, and cuts
NOTE: Occasionally other colors may be used to show special information. These, as a rule,
will be indicated in the margin of information.
3. CONTOUR LINES - Contour lines indicate elevation and relief on maps. A line
representing an imaginary line on the ground, along which all points are at the same elevation.
Each contour line represents an elevation above sea level and the amount of the contour interval
is given in the marginal information. On most maps, the contour lines are printed red-brown,
starting at zero elevation. Every fifth contour line is a heavier brown line. These heavy lines are
known as index contour lines. Also, the elevation will be given along this heavy brown line.
- The spacing of the lines indicates the nature of the slope. This has important military
significance.
- The closer the contour lines the steeper the terrain.
Figure 3. Bar Scale
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Land Formations
Hill - a point or small area of high ground (see figure 4).
Figure 4
Valley - a stream course, which has at least, a limited extent of level ground bordered on
the sides by higher ground. Contours indicate a valley that is a “U" shape, and the curve
of the contour crossing always points up (see figure 5).
Figure 5
Draw - a less developed stream in which there is essentially no level ground and
therefore, little or no maneuver room within its confines. The ground slopes upward on
each side and towards the head of the draw. Contour lines indicating a draw are 'V"
shaped, with the point of the 'V" toward the head of the draw (see figure 6).
Figure 6
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Ridge - a line of high ground, normally with minor variations along its crest. The ridge is
not simply a line of hills but rather the ridge crest are higher than the ground on both
sides of the ridge (see figure 7).
Figure 7
Saddle - a dip or low point along the crest of a ridge. A saddle is not necessarily the
lower ground between two hilltops; it may simply be a dip or break along an otherwise
level ridge rest (see figure 8).
Figure 8
Depression - a low point or sinkhole surrounded on all sides by higher ground (see figure
9).
Figure 9
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Cliff - a vertical, or near vertical, slope. When a slope is so steep that it cannot be shown
at the contour interval, it is shown by a ticked line carrying contours. The ticks always
point toward lower ground (see figure 10).
Figure 10
4. MEASURING DISTANCE
Straight Line Distance - to measure line distance between two points:
- Lay a straight strip of paper on the map so the edge touches the center of both points.
- Make a tick mark on the edge of the paper at each point.
- Lay the paper strip along the scale that corresponds to the unit of measure you are
working with.
- Place the right tick mark of the paper strip on the largest full unit on the primary scale
(to the right of zero), allowing the remainder to fall on the extension of the scale (to the
left of zero).
Curved or Irregular Distance - to measure distance along a winding road, stream, or any other
curved line:
- Make a tick mark near one end of the irregular line to be measured.
- Align the paper strip along the center of the first straight portion of line.
- Make a tick mark at the other end of that portion on both the paper strip and the map.
- Keeping both tick marks together, pivot the strip at the second tick mark until another
straight portion of that line is aligned.
- Continue this process until the measurement is completed, then place the paper strip on
the appropriate bar scale and determine the distance measured.
Pace Count
When navigating, one must know his or her pace count to accuratlry record distance covered:
- Record your count in 100-meter increments.
- Step off with your left foot and count every time it hits the deck.
- Record your 100-meter increments by putting a knot in a rope or piece of string.
(Example: A student is walking an azimuth of 25°. That person must travel in this
direction for 500 meters. The students pace count is 65 paces for 100 meters. To figure
out how many paces the student must take – multiply your pace count by the distance.)
DISTANCE divide by 100 x Pace Count (65).
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5. LOCATE POSITION ON A MAP (see figure 11)
In order to locate the position on a map or navigate, there are certain tools that need to be
utilized. One of these tools is the protractor. There are several types of protractors. All of
them divide the circle into units of angular measure, and each has a scale around the outer
edge and an index mark.
- The index mark is the center of the protractor circle from which all directions are
measured.
- The military protractor contains two scales; one in degrees (inner scale) and one in mils
(outer scale).
- This protractor represents the azimuth circle.
- The degree scale is graduated from 0
°
to 360
°
; each tick mark on the degree scale
represents one degree. A line from 0
°
to 180
°
is called the base line of the protractor.
Where the base line intersects the horizontal line, between 90
°
and 270
°
, is the index or
center of the protractor.
- When using the protractor, the base line is always oriented parallel to a north-south grid
line. The 0
°
or 360
°
mark is always toward the top or north on the map and the 90
°
mark is to the right.
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The grid system
System which tells the reader where specific locations or points are (see figure 12). A network
of lines, in the form of squares, placed on the face of the map. These squares are somewhat like
the blocks formed by the street system of a city. The "streets" in a grid all have very simple
names. The names are all numbers. Every tenth line is made heavier in weight. This will help
you find the line you are looking for. Each grid line on the map has its own number. These
numbers appear within the map on the line itself. Four digit numbers identify a 1000 square
meter grid square. Six digits identify a 100-meter grid square. Eight digits identify a 10-meter
grid square. To locate a point by grid reference is a simple matter. We follow a simple rule of
map reading: READ RIGHT AND UP
READ UP
507
4 Digit Step 2
4 Digit Step 1
6 Digit Step 3
8 Digit Step 4
Figure 12. Grid System
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6. LENSATIC COMPASS The primary instrument used to determine and maintain direction
during land navigation.
Parts of the Compass (see figure 13)
- Thumb loop - Graduated straight edge
- Short luminous line - Lens
- Luminous sighting dots - Fixed index line
- Luminous magnetic arrow, "Magnetic North" - Bezel ring
- Sighting slot - Cover
- Sighting wire - Rear sight
- Floating Dial – in both mils and degrees - Base
Compass Precautions
- Handle the compass with care. The dial is set with a delicate balance and shock could
damage it.
- Reading should never be taken near visible masses of metal or electrical circuits.
- In cold weather, always carry the compass in its carrier outside your outer layer of
clothing. If it is carried inside your clothing close to your body, it will fog when
exposed to the cold air.
Compass terms and concepts
Azimuth - an angle measured in a clockwise direction from a north base line.
Grid Azimuth
- The heading due east is an azimuth of 90
°
- South - 180
°
- West - 270
°
- North - 360 or 0
°
. When using an azimuth, the point from which the azimuth
originates is imagined to be the center of the azimuth circle.
Figure 13. Lensatic Compass
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Obtaining a Grid Azimuth
- On your map draw a line connecting two points
Point A represents your present location
Point B represents your destination
- Place the index of the protractor on point A.
- Ensure the 0
°
and the 180
°
base line is parallel with the vertical grid lines on your
map.
- Read the azimuth from the degree (inside) scale; this is the grid azimuth from point
A to point B.
Back Azimuth
- Back azimuth is the reverse direction of a forward azimuth.
- It is comparable to doing an about face. To obtain a back azimuth from an azimuth
less than 180
°
, add 180
°
. If the azimuth is 180
°
or more, subtract 180.
LESS
ADD
MORE
SUBTRACT
Methods For Holding The Compass - The lensatic compass is used to determine or follow
magnetic azimuth both day and night. There are two recommended positions for holding the
compass when navigating:
Compass-to-Cheek Method - Recommended when determining the azimuth to a distant
object.
- Raise the cover (with the sighting wire) straight up and raise the sight (lens) to an
angle about 45
°
above the compass glass.
- Turn the thumb loop all the way down and put your thumb through it. Form a loose
fist under the compass to steady it with your other hand, and raise up to eye level.
- Look through the sighting slot, and align the compass by centering the sighting wire
in the sighting slot.
- Keeping the compass level and the sights aligned, rotate your entire body until the
sighting wire is aligned on a distant object.
- Now glance down through the lens and read the magnetic azimuth under the fixed
index line on the glass.
Center-Hold Position (see figure 14)
- Recommended holding position for a predetermined azimuth, both during the day
and night (you do not need to remove your helmet, weapon, grenades, or magazines
as long as they are not near the compass).
- Open the cover until it forms a straight edge.
- Pull the eyepiece to the rear most position.
- Next, place your thumb through the thumb loop.
- Form a steady base with your remaining fingers.
- Using your other hand, form a solid base for your compass.
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- To measure an azimuth, simply turn your entire body toward the object. While
pointing the compass cover directly at the object, look down and read the azimuth
from beneath the black index line.
Figure 14. Center-Hold Position
Compass Use at Night
- All the luminous features on the compass will be used.
- The lensatic compass has two glass faces, one under the other. The top glass (bezel
ring) rotates; each click means it has turned three degrees.
- Turn the bezel 30 clicks to the left (counter clockwise); this is a total of 90
°
.
- Using the center-hold method, rotate your body and compass until the magnetic
north seeking arrow is directly aligned under the short luminous line on the bezel
ring. Your compass is now set on magnetic azimuth of 90
°
.
- Now all you have to do to march on this azimuth line at night is keep the magnetic
north seeking arrow and the short luminous line aligned and follow the direction of
the luminous dots on the cover of the compass.
7. ORIENTATION OF A MAP
A map is oriented when it is in position with north and south corresponding to north and
south on the ground.
Orienting a map with a compass
- With the map in a horizontal position, the compass straight edge is placed parallel to a
north-south grid with the cover of the compass pointing toward the top of the map.
- This will place the black line on the dial of the compass parallel to grid north.
- Since the needle on the compass points to magnetic north, we have a declination
diagram on the face of the compass formed by the index line and the compass needle.
- Rotate the map and compass until the direction on the declination diagram formed by
the black index line and the compass needle match the directions shown on the
declination diagram printed on the margin of the map. The map is then oriented.
- If the magnetic north arrow on the map is to the left of grid north, the compass reading
will equal the GM angle (given in the declination diagram).
- If the magnetic north is to the right of the grid north, the compass reading will equal
360 minus the GM angle.
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Orienting Without A Compass: Terrain Association
- When a compass is not available, map orientation requires a careful examination of the
map and the ground to find linear features common to both, such as roads, railroads,
fence lines, power lines, etc.
- By aligning the feature on the map with the same feature on the ground, the map is
oriented.
- Orientation by this method must be checked to prevent the reversal of directions that
may occur if only one linear feature is used. Aligning two or more of these features
may prevent this reversal.
Determining location by map and compass
Basic method for determining locations on a map
Inspection and Estimation
- Usually the easiest
- Carefully survey road systems and topographical features in the immediate
vicinity.
Orient the map to the ground
- Identify some prominent characteristic such as a road, junction, bridge, stream
etc., which you can see on the ground and unmistakably identify on your map.
90
°
Offset method
To bypass enemy positions or obstacles and stay oriented, detour around the obstacle by
moving at right angles for specified distances. Use this formula:
Right add 90
°
; Left subtract 90
°
(RALS) (see figure 15)
Figure 15. 90
o
Offset Method
REFERENCES:
Map Reading and Land Navigation, FM 3-25.26, Ch 2, 6, 9, 10, 11
ITS, (May 2001), Pgs 1-18-1 through 1-18-42
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Land Navigation Review
1. List and describe the three different types of north?
2. A six digit grid coordinate gets you to within how many meters of your intended target?
3. Identify the two methods for holding a compass?
4. Describe the purpose of a contour line?
5. Explain the different methods of measuring distance on a map?