LAND NAVIGATION

1
LAND NAVIGATION
LAND NAVIGATION
N
LAND NAVIGATION
W
E
S
LAND NAVIGATION
2
MAP

• A LINE DRAWING TO SCALE OF A PORTION OF THE
  Earth's SURFACE AS SEEN FROM ABOVE.
• MARGINAL DATA - THE INFORMATION THAT IS PROVIDED
  IN THE AREA AROUND THE OUTSIDE OF THE MAP. TO
  INCLUDE THE GM ANGLE, MAP SHEET, NUMBER ELEVATION
  CONTOUR INTERVAL AND SUPPLEMENTARY INTERVAL

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COLORS ON THE MAP

• 5 MAJOR COLORS ON THE MAP
• BLACK - MAN MADE FEATURES ROADS
  /MINES/QUARRY/BUILDINGS
• RED - CLASSIFICATION OF MAN MADE FEATURES
  DIFFERENT ROADS AND BUILT UP AREAS
• BLUE - WATER, DRAINAGE, STREAM, SWAMP, LAKE
• GREEN - VEGETATION, ORCHARD, GRASSLAND
• BROWN - ELEVATION AND RELIEF LINES

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TERRAIN FEATURES

• 8 TERRAIN FEATURES
• 5 MAJOR
• HILL
• RIDGE
• VALLEY
• SADDLE
• DEPRESSION
• 3 MINOR
• DRAW
• SPUR
• CLIFF

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BASE LINES

• TRUE NORTH
• A LINE FROM ANYWHERE ON THE EARTH TO THE NORTH
  POLE
• MAGNETIC NORTH
• DIRECTION TOWARD THE MAGNETIC NORTH POLE.
• GRID NORTH
• ESTABLISHED BY VERTICAL LINES ON THE MAP.

6
THE NORTH BASELINES
N
G N or y
True North
Magnetic North
Grid North
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BACK AZIMUTH

• OPPOSITE THE DIRECTION OF AZIMUTH
• TO OBTAIN A BACK AZIMUTH
• IF THE AZIMUTH IS LESS THAN 180O , THEN ADD 180O
  TO THE AZIMUTH.
• IF THE AZIMUTH IS MORE THAN 180O, THEN SUBTRACT
  180O FROM THE AZIMUTH.
• THE BACK AZIMUTH FOR 180O IS 0O OR 360O

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BACK AZIMUTH
Below 180o 180o Above 180o - 180o Example
115o -180o 295o
0o or 360o
295o
Back azimuth
90o
270o
Origin
180o
115o
180o
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INTERSECTION

• THE LOCATION OF AN UNKNOWN POINT BY SUCCESSFULLY
  OCCUPYING AT LEAST TWO KNOWN POSITIONS ON THE
  GROUND AND THEN SHOOTING COMPASS AZIMUTHS FROM
  THE KNOWN POINTS TO THE UNKNOWN LOCATION. WHERE
  THE TWO LINES INTERSECT ON THE MAP IS THE
  LOCATION OF THE UNKNOWN LOCATION.

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INTERSECTION
GN
Unknown location
C
A
1. A, determines azimuth to C 2. B,
determines azimuth to C 3. Both azimuths are
converted and then plotted from their
respective points 4. Where the azimuths
intersect is the unknown location.
B
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RESECTION

• THE METHOD OF LOCATING ONES POSITION ON A MAP BY
  DETERMINING THE GRID AZIMUTH TO AT LEAST TWO WELL
  DEFINED AND EASILY RECOGNIZABLE LOCATIONS THAT
  CAN BE PINPOINTED ON THE MAP.

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RESECTION
GN
B
C
A (You are here)
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MODIFIED RESECTION

• THE METHOD OF LOCATING ONES POSITION ON THE MAP
  WHEN THE PERSON IS LOCATED ON A LINEAR TERRAIN
  FEATURE ON THE GROUND, SUCH AS A ROAD, CANAL, OR
  STREAM.
• FIND A POINT THAT IS IDENTIFIABLE ON THE MAP AND
  GROUND. DETERMINE THE MAGNETIC AZIMUTH TO THE
  POINT THEN CONVERT IT TO A GRID AZIMUTH. CONVERT
  THE GRID AZIMUTH TO A BACK AZIMUTH.USE A
  PROTRACTOR TO DRAW THE BACK AZIMUTH TOWARD YOUR
  UNKNOWN POSITION. YOUR LOCATION IS WERE THE LINE
  CROSSES THE LINEAR FEATURE.

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MODIFIED RESECTION
GN
Known location
B
Unknown location
A
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ROAD DISTANCE

• WHAT IS THE ROAD DISTANCE MEASURED IN METERS FROM
  RD JUNCTION IN GRID SQUARE EG 0284 TO BM 83 IN
  GRID EG 0787?
• ROAD DISTANCE IN METERS FROM ROAD JUNCTION EH
  0802 0227 TO ROAD JUNCTION AT EG 1074 9666?

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ROAD DISTANCE ANSWER

• 1) 6,070 - 6,170 - 6,270
• 2) 6,910 - 7010 - 7110

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BACK AZIMUTH

• BACK AZIMUTH OF
• 35 DEGREES
• 340 DEGREES
• 210 DEGREES
• 125 DEGREES

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BACK AZIMUTH ANSWERS

• 215 DEGREES
• 160 DEGREES
• 30 DEGREES
• 305 DEGREES

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INTERSECTION

• ID THE OBJECT OR FEATURE LOCATED ALONG A MAGNETIC
  AZIMUTH OF 32 DEGREES FROM BM 86 IN GRID SQUARE
  EG 05 89 AND A MAGNETIC AZIMUTH OF 71 DEGREES
  FROM THE BRIDGE IN GRID EG 0393.

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INTERSECTION

• ID THE OBJECT OR FEATURE LOCATED ALONG A MAGNETIC
  AZIMUTH OF 35 DEGREES FROM BM 86 IN GRID SQUARE
  EG 05 89 AND A MAGNETIC AZIMUTH OF 71 DEGREES
  FROM THE BRIDGE IN GRID EG 0393.
• RAILROAD BRIDGE EG 10 93

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RESECTION

• YOU ARE AT A STRUCTURE IN AN UNKNOWN LOCATION YOU
  DETERMINE THAT SPOT ELEVATION 215 IN GRID SQUARE
  1686 IS ON A MAGNETIC AZIMUTH OF 358 1/2 DEGREES.
  YOU CAN ALSO SEE A WATER TOWER IN GRID EG 1185,
  ON A MAGNETIC AZIMUTH OF 290 DEGREES WHAT IS THE
  EIGHT DIGIT GRID TO YOUR LOCATION?
• ONE OF YOUR SQD LEADERS ON A PATROL DETERMINES
  THE MAGNETIC AZIMUTH FROM HIS POSITION TO THE TV
  RELAY TOWER IN GRID SQUARE EG 1287 TO BE 3
  DEGREES AND THE MAGNETIC AZIMUTH FROM HIS
  LOCATION TO THE SE 199 IN GRID SQUARE EG 1385 TO
  BE 77 DEGREES. WHAT IS HIS LOCATION THAT HE
  SHOULD REPORT TO YOU (ID THE FEATURE)?

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RESECTION
YOU ARE AT A STRUCTURE IN AN UNKNOWN LOCATION YOU
DETERMINE THAT SPOT ELEVATION 215 IN GRID SQUARE
1686 IS ON A MAGNETIC AZIMUTH OF 358 1/2 DEGREES.
YOU CAN ALSO SEE A WATER TOWER IN GRID EG 1185,
ON A MAGNETIC AZIMUTH OF 290 DEGREES WHAT IS THE
EIGHT DIGIT GRID TO YOUR LOCATION? EG 1519
8243
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RESECTION

• ONE OF YOUR SQD LEADERS ON A PATROL DETERMINES
  THE MAGNETIC AZIMUTH FROM HIS POSITION TO THE TV
  RELAY TOWER IN GRID SQUARE EG 1287 TO BE 3
  DEGREES AND THE MAGNETIC AZIMUTH FROM HIS
  LOCATION TO THE SE 199 IN GRID SQUARE EG 1385 TO
  BE 77 DEGREES. WHAT IS HIS LOCATION THAT HE
  SHOULD REPORT TO YOU (ID THE FEATURE)?
• CEMETERY AT GRID EG 11 85

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MODIFIED RESECTION

• YOU ARE LOCATED ON SCATTER CREEK WHICH RUNS
  THROUGH EG 00 86 AND EG 09 85 THE MAGNETIC
  AZIMUTH FROM YOUR POSITION TO LEMON HILL EG 00949
  8890 IS 14 DEGREES. WHAT IS YOUR LOCATION WITHIN
  10 METERS?

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MODIFIED RESECTION

• YOU ARE LOCATED ON SCATTER CREEK WHICH RUNS
  THROUGH EG 00 86 AND EG 09 85 THE MAGNETIC
  AZIMUTH FROM YOUR POSITION TO LEMON HILL EG
  09498890 IS 14 DEGREES. WHAT IS YOUR LOCATION
  WITHIN 10 METERS?
• EG 0758 8625

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QUESTIONS/ISSUES