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# Land Navigation - PowerPoint PPT Presentation

Land Navigation. Determine Location on the Ground & Navigate from One Point to Another. Map Basics. Definition: A map is a mathematically determined representation of the Earth’s surface systematically plotted to scale upon a plane surface. Map Basics: . Map Scales

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Presentation Transcript

Determine Location on the Ground

&

Navigate from One Point to Another

Map Basics
• Definition: A map is a mathematically determined representation of the Earth’s surface systematically plotted to scale upon a plane surface.
Map Basics:
• Map Scales
• Representative Fraction is the scale of the map which expresses the ratio of horizontal distance on the map to the corresponding horizontal distance on the ground:
• 1:25,000 SCALE.
• 1:50,000 SCALE
• 1:100,000 SCALE
• 1:250,000 SCALE
• The smaller the number on the bottom, the larger the scale of the map
Map Basics: Colors
• Black: Man-made objects
• Buildings, some roads, cultural, etc.
• Red: Main roads
• Also some special features
• Blue: Water features
• Lakes, rivers, ponds, ocean, etc.
• Green: Vegetation
• Forrest, orchard, etc.
• Brown: Relief features
• Contour lines.

### Terrain Features

Terrain Features - Major
• Hill
• Valley
• Ridge
• Depression

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HILL

A hill is an area of high ground. From a hilltop, the ground slopes down in all directions. A map depicts a hill by showing contour lines forming concentric circles (circles having a common center). The inside of the smallest closed circle is the hilltop

VALLEY

A valley is a stretched out groove in the land, usually formed by streams or major rivers. If standing in a valley, three directions offer high ground, while the fourth direction offers low ground. The contour lines forming a valley are either U-shaped or V-shaped. The closed end of the contour line (U or V) always points upstream or toward higher ground.

RIDGE

A ridge is a sloping line of high ground. If you are standing on the centerline of a ridge, you will normally have low ground in three directions and high ground in one direction with varying degrees of slope. If you cross a ridge at right angles, you will climb steeply to the crest and then descend steeply to the base. Contour lines forming a ridge tend to be U-shaped or V-shaped. The closed end of the contour line points away from high ground.

A saddle is a dip or low point between two areas of higher ground. A saddle is not necessarily the lower ground between two hilltops; it may be simply a dip or break along a level ridge crest. If you are in a saddle, there is high ground in two opposite directions and lower ground in the other two opposite directions.

DEPRESSION

A depression is a low point in the ground or a sinkhole. It could bedescribed as an area of low ground surrounded by higher ground in all directions, or simply a hole in the ground. Usually only depressions that are equal to or greater than the contour interval will be shown. On maps, depressions are represented by closed contour lines that have tick marks pointing toward low ground.

Terrain Features - Minor
• Draw
• Spur

Terrain Features - Supplementary

• Cliff
• Cut
• Fill

DRAW

A draw is a stream course that is less developed than a valley. In a draw, there is essentially no level ground and, therefore, little or no maneuver room within its confines. If you are standing in a draw, the ground slopes upward in three directions and downward in the other direction. A draw could be considered as the initial formation of a valley.

SPUR

A spur is a short, continuous sloping line of higher ground, normally jutting out from the side of a ridge. A spur is often formed by two roughly parallel streams cutting draws down the side of a ridge. The ground will slope down in three directions and up in one. Contour lines on a map depict a spur with the U or V pointing away from high ground.

CLIFF

A cliff is a vertical or near vertical feature; it is an abrupt change of the land. When a slope is so steep that the contour lines converge into one “carrying” contour of contours, this last contour line has tick marks pointing toward low ground. Cliffs are also shown by contour lines very close together and, in some instances, touching each other.

CUT

A cut is a man-made feature resulting from cutting through raised ground, usually to form a level bed for a road or railroad track. Cuts are shown on a map when they are at least 10 feet high, and they are drawn with a contour line along the cut line. This contour line extends the length of the cut and has tick marks that extend from the cut line to the roadbed, if the map scale permits this level of detail.

FILL

A fill is a man-made feature resulting from filling a low area, usually to form a level bed for a road or railroad track. Fills are shown on a map when they are at least 10 feet high, and they are drawn with a contour line along the fill line. This contour line extends the length of the filled area and has tick marks that point toward lower ground. If the map scale permits, the length of the fill tick marks are drawn to scale.

Determine Direction without a Compass

The sun rises in the east and sets in

the west.

### Determine Elevation

Determine Elevation
• Locate point on the map
• Determine contour interval of map
• Locate index contour line nearest point
• Count number of contour lines up or down that must be crossed to get to point
• Points at top of hill add half the contour interval
• Points at bottom of depression subtract half the contour interval

Compass

Familiarization

### Determine Azimuth

Determine Azimuth

Azimuth: a horizontal angle measured clockwise from a north base line. This north base line could be true north, magnetic north, or grid north. The azimuth is the most common military method to express direction.

• Plot location of two points.
• Use straight edge to draw line between both points (line must be long enough to cross scale on protractor)
• Place the index of the protractor at the point where the drawn line crosses a vertical (north-south) grid line.
• Keeping the index at this point, align the 0-to-180 degree line of the protractor on the vertical grid line.
• Read the value of the angle from the scale; this is the grid azimuth from point A to point B.

A

104°

B

When measuring azimuths on a map, remember that you are measuring from a starting point to an ending point. If a mistake is made and the reading is taken from the ending point, the grid azimuth will be opposite, thus causing the user to go in the wrong direction.

Back Azimuth
• A back azimuth is the opposite direction of an azimuth. It is comparable to doing an "about face."
• Back Azimuth - azimuth taken from a distant point toward your location
• Used in Resection
• Numbers less than 180°: add 180°

Ex: azimuth = 145°, resection = 145°+180° = 325°

• Numbers greater than 180°: subtract 180°

Ex: azimuth = 270°, resection = 270°-180° = 90°

### Grid vs. Magnetic Azimuth

The Three Norths

• True North: A line from any point on the earth's surface to the north pole. All lines of longitude are true north lines.
• Magnetic North: The direction to the north magnetic pole, as indicated by the north-seeking needle of a magnetic instrument. ie: a compass
• Grid North: The north that is established by using the vertical grid lines on the map.

Grid-Magnetic Angle: The G-M angle value is the angular size that exists between grid north and magnetic north. Azimuths translated between map and ground will be in error by the size of the declination angle if not adjusted for it.

Converting Grid/Magnetic Azimuths

Since the location of magnetic north does not correspond exactly with the grid-north lines on the maps, a conversion from magnetic to grid or vice versa is needed.

Grid to Magnetic azimuth:

• East G-M angle: subtract
• Ex: GM angle: 21°, grid azimuth: 360° magnetic azimuth: 360°-21°=339°

Magnetic to Grid azimuth:

• East G-M angle: add
• Ex: GM angle: 21°, grid azimuth: 360° magnetic azimuth: 360°+21°=21°
• Refer to the conversion notes with Declination Diagram.

21°

Easterly Declination

*There are no negative azimuths on the azimuth circle; will be between 0° and 360°

ex: -30° = 330°, 380°= 220°

Converting Grid/Magnetic Azimuths

Since the location of magnetic north does not correspond exactly with the grid-north lines on the maps, a conversion from magnetic to grid or vice versa is needed.

Grid to Magnetic azimuth:

• West G-M angle: add
• Ex: GM angle: 30°, grid azimuth: 140°

magnetic azimuth: 140°+30°=170°

Magnetic to Grid azimuth:

• West G-M angle: subtract
• Ex: GM angle: 30°, grid azimuth: 140° magnetic azimuth: 140°-30°=110°
• Refer to the conversion notes with Declination Diagram.

30°

Westerly Declination

*There are no negative azimuths on the azimuth circle; will be between 0° and 360°

ex: -30° = 330°, 380°= 220°

PRACTICAL EXERCISE

1. The G-M angle is 21° east. You plot an azimuth of 146 °. What is your magnetic azimuth? ANSWER: 146°-21° = 125°

2. The G-M angle is 45° west. You plot an azimuth of 30 °. What is your magnetic azimuth? ANSWER: 30°+45° = 75°

3. The G-M angle is 40° east. You plot an azimuth of 15 °. What is your magnetic azimuth? ANSWER: 15°-40° = 335°

4. The G-M angle is 21° east. You shoot an azimuth of 146 °. What is your grid azimuth? ANSWER: 146°+21° = 167°

5. The G-M angle is 45° west. You shoot an azimuth of 30°. What is your grid azimuth? ANSWER: 30°-45° = 345°

6. The G-M angle is 40° east. You shoot an azimuth of 15 °. What is your grid azimuth? ANSWER: 15°+40° = 55°

• Grid to Magnetic azimuth:
• East G-M angle: subtract
• West G-M angle: add
• Magnetic to Grid azimuth:
• East G-M angle: add
• West G-M angle: subtract

Intersection

Intersection is the location of an unknown point by successively occupying at least two (preferably three) known positions on the ground and then map sighting on the unknown location. It is used to locate distant or inaccessible points or objects such as enemy targets and danger areas.

SCENARIO:

We have two OPs located in front of our defensive position. Both OPs can see enemy activity. From OP1, the enemy activity is 32° magnetic and from OP2, it is 322° magnetic. The G-M angle is 18° easterly. What is the enemy’s location?

How to Solve

Step 1:

Identify / plot OPs or

points of reference

Step 2:

Convert azimuth from

magnetic to grid

G-M Angle: 18° east

OP1: 32° magnetic

32° +18° = 50° grid

OP2: 322° magnetic

322° +18° = 140° grid

Step 3:

Using the protractor

Plot first azimuth

- 50° grid

Step 3:

Using the protractor

Plot first azimuth

- 50° grid

Step 4:

Plot second azimuth

- 240° grid

Step 3:

Using the protractor

Plot first azimuth

- 50° grid

Step 4:

Plot second azimuth

- 240° grid

Step 5:

Plot intersection

The enemy will be at the point where the lines intersect.

Bye Bye

Step 3:

Using the protractor

Plot first azimuth

- 50° grid

Step 4:

Plot second azimuth

- 240° grid

Step 5:

Plot intersection

Step 6:

Resection

Resection is the method of locating one's position on a map by determining the grid azimuth to at least two well-defined locations that can be pinpointed on the map. For greater accuracy, the desired method of resection would be to use three or more well-defined locations.

SCENARIO:

Looking out from our position we can see a bridge. Using our compass we determine the azimuth to its location to be 159°. We can also see a large road intersection. The azimuth to its location is 117°. We locate these positions on our map which has a westerly G-M angle of 1°. What is our location?

WHERE AM I?

• Step 1:
• Identify / plot OPs or
• points of reference

Step 2:

-Convert azimuth from

magnetic to grid

G-M Angle: 1° west

Bridge: 159° magnetic

159° - 1° = 158° grid

Road Int: 117° magnetic

117° - 1° = 116° grid

WHERE AM I?

• Step 3:
• Convert azimuth to back azimuth
• Bridge: 158° grid from you
• Back Az: 158° + 180° = 338°
• Road Int: 116° grid from you
• Back Az: 116° + 180° = 296°

Step 4:

• Plot 1st back azimuth
• from bridge 338°

Step 4:

• Plot 1st back azimuth
• from bridge 338°
• Step 5:
• Plot 2nd back azimuth from road intersection 296°

Step 4:

• Plot 1st back azimuth
• from bridge 338°

X

• Step 5:
• Plot 2nd back azimuth from road intersection 296°
• Step 6:
• Plot your position

Your position will be at the point where the lines intersect.

Step 4:

• Plot 1st back azimuth
• from bridge 338°

X

• Step 5:
• Plot 2nd back azimuth from road intersection 296°
• Step 6:
• Plot your position
Quiz
• What is a map?
• What are the three types of North?
• Explain what they represent.
• What standard colors are used on a map?
• What do they represent?
• Explain the 2 main types of contour lines.
• What is an 8-digit grid coordinate?
• How accurate is it is using a 1:25000 coordinate scale?
• Describe the four types of slope and what they look like on a topographic map.

### Identify a Grid

Map Basics: Grid Lines
• A series of straight lines intersecting at right angles forming squares
• Horizontal grid lines run grid west to grid east
• Vertical grid lines run grid south to grid north
• On most military maps a grid square is 1000X1000 meters
• Basic Rule: Read right on the vertical lines, then up on the horizontal grid lines

4-Digit Coordinate: within 1000 meters

• 6-Digit Coordinate: within 100 meters
• 8-Digit Coordinate: within 10 meters
• *The more digits in a grid coordinate, the closer the location.
4-Digit Grid
• Read Right then Up
• Bottom left corner identifies first two digits
• Right:11 Up: 81 ex. 1181e
• Add proper grid zone designator to front
• ex. AB1181
6-Digit Grid
• Read Right then Up
• Bottom left corner identifies first two digits 1181e
• Use coordinate scale to identify last digit
• ex. 115813
• Add proper grid zone designator to front ex: AB115813

8-Digit Grid

50m tick marks

• If point is between 2-100 meter tick marks use the
• 50 meter tick marks to help estimate

8-Digit Grid

2

3

5

6

7

8

9

1

2

3

4

82

9

8

7

6

5

4

AB 11578136

3

2

1

81

4

5

6

7

8

9

12

• Read Right then Up
• Bottom left corner identifies first two digits 1181e
• Use coordinate scale to identify last two digits ex: 11578136
• Add proper grid zone designator to front ex: AB 11578136

### Determine Distance

Determine Distance
• Straight-Line Distance

A straight-line distance is the shortest route between two points.

STEP 1: Use edge of paper and mark distance between points.

Determine Distance
• Straight-Line Distance

STEP 2: Line paper up next to scale to determine distance.

Determine Distance
• Curved or road distances are used when you need to measure the distance along a winding road, stream, or any other route following an irregular course.
• Break curve into series of straight lines and measure from curve to curve
• Line paper up next to scale to determine distance

STEP 1: Mark on your map starting point A and finishing point B.

STEP 2: Place a tick mark near one end of a straight edge piece of paper.

STEP 3: Align the straight edge of the paper with the road on the map so that the tick mark is on the start point and the edge of the paper extends along the route to a point where the route changes direction.

Determine Distance

STEP 4: At the point where the road changes direction and does not follow the edge of the paper, place a tick mark at that point on your map and the piece of paper.

Determine Distance

STEP 5: Rotate the paper so that the tickmark you just made on the paper and map are aligned and the straight edge follows the road until the road changes direction again. As before, place a tickmark on the piece of paper and the map at the location where the road changes direction. Continue this process until you reach Point B.

STEP 6: Now that you have a straight-line measurement, determine the distance on the bar scale the same way to you learned to measure straight-line distances.

Select a Movement Route Using a Map
• Select the route that provides the most favorable tactical advantage and meets the mission requirements.
• If enemy air is active or enemy ground forces are in the area of the route, you must take maximum advantage of cover and concealment.
• If speed of movement is critical, the route should be over the most easily negotiable terrain, avoiding difficult obstacles.
• The route should include movement from one easily distinguishable terrain feature to another.

When ordered to move, you must check the terrain based on the above considerations and select the quickest and safest route.

Navigate from One Point to Another While Dismounted using terrain association

This technique uses terrain or man-made features to serve as landmarks or checkpoints for maintaining direction of movement. In using association, you locate first your position on the map then your destination or objective.

When adjusting your route, consider the following:

• Tactical aspect. Avoid skylining open areas and danger areas like streams or crossings on roads and hilltops. Your tactical concern is survival. The mission is causing you to move to your objective. You need to be sure you get to that objective.
• Ease of movement. Always pick the easiest route that the tactical situation allows.
• Boundaries. It is almost impossible to travel in a straight line, with or without a compass. Pick an axis or corridor to travel along.
• With boundaries to keep you straight, you need to know where, along your corridor, you are. You do this with checkpoints. The best checkpoint is a line or linear feature that you cannot miss.

Note. DO NOT use light-duty roads and trails; there are always more on the ground than the map shows. DO NOT use wood lines, which are rarely permanent.

If you cannot find linear features, use an elevation change—hill or depression, small ridge, or valley. Determine the distance between checkpoints. DISTANCE IS THE CAUSE OF MOST NAVIGATIONAL MISTAKES. Estimate or measure the distance from one checkpoint to another. Trust that distance.

Navigate from One Point to Another While Dismountedusing dead reckoning

Dead reckoning is a technique of following a set route or line for a determined distance. This technique is used on flat terrain, like deserts and swamps. It can be used day or night. To use dead reckoning—

(1) Locate the start point and finish point on the map

(2) Determine the grid azimuth from the start point to the finish point, or to the first intermediate point on the map.

(3) Convert the grid azimuth taken from the map to a magnetic azimuth.

(4) Determine the distance between the start point and the finish point, or any intermediate points on the map.

(5) Convert the map distance to pace count.

(6) Make a thorough map reconnaissance of the area between the start point and the finish point.

a. Before moving from the start point, shoot an azimuth on a well-defined object on the ground in the direction of travel. Remember to travel the distance you determined.

b. Once you have selected a steering point, move toward it, remembering to begin your count. You should have some method devised to keep track of the number of 100 meters you travel.

c. Upon reaching your first steering point, shoot an azimuth to another steering mark, and repeat c, until you reach the finish point.

Determine the effects of terrain on the vehicle when navigating mounted.

Military vehicles are designed to climb 60-percent (30-degree) slopes if the surface is dry and firm. If gravel, vegetation, or mud is on the slope, the practical slope-climbing capability is about 40 percent (20 degrees).

Determine the approximate slope by looking at the route selected on a map.

One contour line in any 100 meters of map distance on that route indicates a 10-percent slope. Two contour lines indicate a 20-percent slope, and so forth. If there are four contour lines in 100 meters, look for another route.

Know the effects of weather on vehicle movement.

Weather can halt mounted movement. Snow and ice are dangerous. Rain and snow affect soil load-bearing ability. Heavy rain may restrict cross-country vehicles to road movement.

Adjust the route to avoid flooded or muddy areas. A stuck vehicle hinders combat capability.

Determine the effects of terrain on the vehicle when navigating mounted.

Terrain Association This is the most used method of navigation. The navigator plans the route for movement from one terrain feature to another.

(1) Determine the start point and destination.

(2) Draw or visualize a straight line between the two points on the map.

(3) Inspect the terrain along that line for ease of movement

After analyzing the terrain, adjust the route by doing the following:

• Consider tactical aspects. Avoid skylining
• Consider ease of movement. Use the easiest possible route. Bypass difficult terrain.
• Use terrain features as checkpoints. Checkpoints must be easily recognizable, from a moving vehicle, under the current light and weather conditions.
• Follow terrain features. Movement and navigation along a valley floor or near or on the crest of a ridgeline are easiest.
• Determine directions. Break the route into smaller segments and determine the rough direction that will be followed. The compass is not needed; use the main points of direction (north, northeast, east, for example).
• Determine distance. Obtain the total distance to be traveled and the approximate distance between checkpoints.
• Plan. Restudy the route selected. Determine where problems may occur and how they may be avoided.
Determine the effects of terrain on the vehicle when navigating mounted.

Dead reckoning means moving a set distance along a set line. It involves moving so many meters along a set line, usually an azimuth in degrees.

Dead reckoning with steering marks. This procedure is the same as it is for on foot travel.

(a) Dismount from the vehicle.

(b) Move away from the vehicle (about 50 meters).

(c) Set the azimuth on the compass and choose a steering mark (rock, tree, hilltop) in the distance on that azimuth.

(d) Remount and have the driver identify the steering mark. Proceed to it in as straight a line as possible.

(e) On arrival at the steering mark or when direction is changed, repeat paragraphs (a) through (c) for the next leg of travel.