1. Map Reading III Determining Direction
GRC JROTC
COL(R) Alexander

2. Outline Purpose Polar Coordinates & Practical Exercise
Intersection & Practical Exercise
Resection & Practical Exercise
Summary
Conclusion

3. Polar Coordinates Plot an azimuth from a known point.EG
Plot the distance from the known point along the azimuth line.
56 degrees
The Polar Coordinate is at the end of the azimuth/distance line.
3400 M
Tenino Map

4. ENSURE your protractor is straight UP & DOWN !
STEP 1: PLACE THE INDEX MARK OF THE PROTRACTOR AT THE
CENTER OF MASS ON THE POINT FROM WHICH YOU ARE
MEASURING.
ENSURE your protractor is straight UP & DOWN !
POINT 1 EG
Tenino Map

5. 56 PNT 1 STEP 2: LOCATE THE DESIRED AZIMUTH ON THE PROTRACTOR
SCALE AND PLACE A DOT ON THE MAP AT THIS AZIMUTH.
EXAMPLE: 56 DEGREES
EXAMPLE: 56 DEGREES 56
PNT 1

6. PNT 1 STEP 3: REMOVE THE PROTRACTOR AND CONNECT THE POINT
AND DOT WITH A STRAIGHT LINE.
PNT 1

7. 56o PNT 1 PNT 1 STEP 3: REMOVE THE PROTRACTOR AND CONNECT THE POINT
AND DOT WITH A STRAIGHT LINE.
STEP 3. REMOVE THE PROTRACTOR AND CONNECT THE POINT
AND DOT WITH A STRAIGHT LINE.
56o
PNT 1

8. STEP 4: SELECT THE APPROPRIATE SCALE MEASUREMENT AND PLACE A PAPER STRAIGHT EDGE ON THE SCALE.
EXAMPLE: DISTANCE IN METERS
Piece of white paper

9. STEP 5: DETERMINE THE DESIRED DISTANCE TO MEASURE FROM THE SCALE AND MARK THE PAPER AT THIS DISTANCE USING TICK MARKS.
EXAMPLE: METERS ( )
3400 M
100
Each alternating block is 100 Meters

10. STEP 6: ALIGN THE STRAIGHT EDGE WITH THE AZIMUTH LINE.
ENSURE THE FIRST TICK MARK IS CENTER MAST
ON THE KNOWN POINT.
3400 Meters
PNT 1

11. PNT 1 STEP 4: PLACE A DOT ON THE MAP AT THE SECOND TICK MARK
FROM THE STRAIGHT EDGE ON THE MAP.
THE POSITION OF THE SECOND TICK MARK
IS THE POSITON OF THE UNKNOWN POINT.
PNT 1

12. 1 3 5 5 8 8 5 5 USE Protractor ! GRID SQUARE
_____ _____ _____ _____ _____ _____ _____ _____
GRID SQUARE

13. REMOVE THE STRAIGHT EDGE AND DETERMINE THE GRID
COORDINATE TO THE SECOND POINT.
56o
Read the Grid: EG
3400 M
PNT 1

14. Practical Exercise & ANSWERS
1. QUESTION: What are the polar coordinates plotted from the center of the Reservoir at EG at a grid azimuth of 158 degrees and a distance of 1700 meters? Determine the GRID & Describe this location?
EG (road intersection next to a Pit)
QUESTION: What are the polar coordinates plotted from the water tower in grid square EG1185 at a grid azimuth of 30 degrees and a distance of 3500 meters? Determine the GRID & Describe the terrain feature located here?
EG (spur)
QUESTION: What are the polar coordinates plotted from the Deschutes fire tower in grid square EG at a grid azimuth of 303 degrees and a distance of 2600 meters? Determine the GRID & Describe the terrain feature located here?
EG (saddle)

15. Intersection (determining the location of an object/point)
Determine the position (GRID LOCATION) of an unknown point (or object) by occupying at least two (2), but preferably three (3) known locations.
Determine the azimuth (magnetic-compass) to the unknown point from these locations
Plot the azimuths (grid-map) from the positions to locate the to the unknown point by their intersections on the map.

16. You must be able to accurately locate (a GRID)
STEP 1: SIGHT THE UNKNOWN POINT (or OBJECT) ON THE GROUND.
STEP 2: LOCATE YOUR POSITION ON THE GROUND
AND MARK IT ON THE MAP. ?
You must be able to accurately locate (a GRID)
your POSITION !
POS 1

17. You must be able to accurately locate your POSITION !
STEP 2. LOCATE YOUR POSITION ON THE GROUND
AND MARK IT ON THE MAP.
EXAMPLE: ROAD JUCTION AT EG
POS 1
You must be able to accurately locate your POSITION !

18. STEP 3. DETERMINE THE MAGNETIC AZIMUTH FROM THE ROAD JUNCTION TO THE ENEMY POSITION (with a COMPASS).
59 DEGREES
MAGNETIC
POS 1

19. BUT WAIT ! WHAT DO YOU HAVE TO DO WITH THAT COMPASS AZIMUTH BEFORE YOU CAN USE IT ON A MAP?
59 DEGREES
MAGNETIC
POS 1

20. STEP 4: CONVERT THE MAGNETIC AZIMUTH TO A GRID (map) AZIMUTH.
MAGNETIC AZIMUTH: 59 DEGREES
EASTERLY G-M ANGLE: +21 DEGREES
GRID AZIMUTH: DEGREES
Tenino Map

21. 80 STEP 5: DRAW A LINE FROM THE ROAD JUNCTION
ALONG THE 80 DEGREE GRID AZIMUTH. 80
POS 1

22. STEP 6: MOVE TO (or contact someone else who can provide a magnetic azimuth) A SECOND POSITION WHERE THE UNKNOWN POINT/OBJECT CAN BE SEEN AND OBTAIN ANOTHER COMPASS AZIMUTH TO THE OBJECT AND MARK THE AZIMUTH ON THE MAP.
POS 1
POS 2

23. STEP 6: MOVE TO (or contact someone else who can provide a magnetic azimuth) A SECOND POSITION WHERE THE UNKNOWN POINT/OBJECT CAN BE SEEN AND OBTAIN ANOTHER COMPASS AZIMUTH TO THE OBJECT AND MARK THE AZIMUTH ON THE MAP..
EXAMPLE: ROAD JUCTION AT EG
POS 2
POS 1

24. STEP 7: DETERMINE THE MAGNETIC AZIMUTH FROM THE SECOND ROAD JUNCTION TO THE OBJECT / POSITION.
79 DEGREES
MAGNETIC
POS 2

25. BUT WAIT ! WHAT DO YOU HAVE TO DO WITH THAT COMPASS AZIMUTH BEFORE YOU CAN USE IT ON A MAP?
POS 1
79 DEGREES
MAGNETIC
POS 2

26. STEP 4: CONVERT THE MAGNETIC AZIMUTH TO A GRID AZIMUTH.
MAGNETIC AZIMUTH: 79 DEGREES
EASTERLY G-M ANGLE: +21 DEGREES
GRID AZIMUTH: DEGREES

27. STEP 9. DRAW A LINE FROM THE SECOND ROAD
STEP 9. DRAW A LINE FROM THE SECOND ROAD JUNCTION ALONG THE 100 DEGREE GRID AZIMUTH.
POS 2
100
POS 1

28. STEP 10: WHERE THE LINES CROSS IS THE LOCATION OF THE UNKNOWN POINT or OBJECT (enemy tank).
POS 2 EG
POS 1

29. IT’S DESIRABLE TO REPEAT THE PROCEDURE FROM A THIRD POINT TO INCREASE THE ACCURACY.
EXAMPLE: ROAD JUNCTION AT EG
POS 3
POS 2
POS 1
MAGNETIC AZIMUTH: 128 DEGREES
MAGNETIC AZIMUTH: 128 DEGREES
EASTERLY G-M ANGLE: +21 DEGREES
EASTERLY G-M ANGLE: +21 DEGREES
GRID AZIMUTH: 149 DEGREES

30. POS 3
POS 2
POS 1
NOTICE THAT THE LINES FROM THE FIRST AND SECOND
POINT FORM A SHALLOW ANGLE.
THIS DECREASES ACCURACY. WHENEVER POSSIBLE, CHOOSE LOCATIONS THAT WILL GIVE YOU A LARGER ANGLE (CLOSER TO 90 DEGREES LIKE POSITION 3.)

31. NOTE: WHEN TRIANGULATING, THE CENTER OF
THE TRIANGLE IS RECORDED AS THE
LOCATION. EG

32. Practical Exercise 1 of 2
YOUR SQUAD OCCUPIES 2 OBSERVATION POSTS. THE TEAM AT THE WATER TOWER IN GRID SQUARE EG 0985 SEES THE ENEMY AT A MAGNETIC AZIMUTH OF 351 DEGREES. THE SECOND TEAM, LOCATED AT THE WATER TOWER IN GRID SQUARE EG 1185 SEES THE ENEMY AT A MAGNETIC AZIMUTH OF 300 DEGREES.
QUESTION: WHAT IS THE GRID LOCATION OF THE ENEMY?
ANSWER: GRID COORDINATE EG

33. Practical Exercise 2 of 2
YOUR SQUAD IS OPERATING AS AN OBSERVATION TEAM & YOU
SEE SIX (6) ENEMY HELICOPTERS LAND & THEN DISAPPEAR FROM YOUR SIGHT. PRIOR TO THE HELICOPTERS DISAPPEARING, YOU SHOT A MAGNETIC AZIMUTH TO THE LOCATION WHERE YOU SAW THEM LAND. THIS MAGNETIC AZIMUTH IS 316 1/2 DEGREES. YOUR LOCATION IS THE BRIDGE IN GRID SQUARE EH YOU CONTACT YOUR OTHER TEAM LOCATED IN THE ZION CHAPEL TOWER AT GRID SQUARE EH THEY HAVE A SIGHTING OF SIX (6) ENEMY HELICOPTERS AT A MAGNETIC AZIMUTH OF 229 1/2 DEGREES. BOTH YOUR TEAMS PERFORM AN INTERSECTON.
QUESTION: WHAT IS THE GRID LOCATION AND THE TYPE OF TERRAIN WHERE THE SIX (6) ENEMY HELICOPTERS LANDED?
ANSWER: GRID LOCATION EH , DEPRESSION.

34. Resection (determining YOUR location using known objects/points)
Determine the position of an unknown point (YOU) by locating at least two (2), but preferably three (3) known locations (points on the ground).
Determine the azimuth to the known points from the unknown point/location.
Plot the back azimuths from the known points to locate the unknown point by their intersections.

35. STEP 1: LOCATE A FEATURE OR OBJECT THAT IS
STEP 1: LOCATE A FEATURE OR OBJECT THAT IS IDENTIFIABLE ON BOTH THE GROUND AND THE MAP AND MARK THE MAP LOCATION.
EXAMPLE: TOWER LOCATED AT EG
“Where in the heck am I???”

36. EXAMPLE: TOWER LOCATED AT EG 1804 8759
KP 1
STEP 1: LOCATE A FEATURE OR OBJECT THAT IS
IDENTIFIABLE ON BOTH THE GROUND AND
THE MAP AND MARK THE MAP LOCATION.

37. STEP 2: MEASURE THE MAGNETIC AZIMUTH (w/ your COMPASS) TO THE KNOWN POSITION (Tower) AND CONVERT THE MAGNETIC AZIMUTH TO A GRID AZIMUTH.
29 DEGREES
MAGNETIC

38. MAGNETIC AZIMUTH: 29 DEGREES
STEP 2: MEASURE THE MAGNETIC AZIMUTH TO THE KNOWN POSITION AND CONVERT THE MAGNETIC AZIMUTH TO A GRID AZIMUTH.
MAGNETIC AZIMUTH: 29 DEGREES
EASTERLY G-M ANGLE: +21 DEGREES
GRID AZIMUTH: DEGREES

39. GRID BACK AZIMUTH: 230 DEGREES
STEP 3. CHANGE THE GRID AZIMUTH TO A BACK AZIMUTH & DRAW A LINE FROM THE KNOWN POSITION (Tower) BACKWARD TOWARD YOUR UNKNOWN POSITION.
GRID AZIMUTH: DEGREES
ADD: DEGREES
GRID BACK AZIMUTH: DEGREES

40. KP 1
230
STEP 3: CHANGE THE GRID AZIMUTH TO A BACK AZIMUTH & DRAW A LINE FROM THE KNOWN POSITION (Tower) BACKWARD TOWARD YOUR UNKNOWN POSITION.

41. STEP 4: LOCATE A SECOND FEATURE OR OBJECT THAT IS IDENTIFIABLE ON BOTH THE GROUND & THE MAP AND MARK THE MAP LOCATION.
EXAMPLE: BRIDGE LOCATED AT EG

42. KP 1
EXAMPLE: BRIDGE LOCATED AT EG
KP 2
STEP 4: LOCATE A SECOND FEATURE OR OBJECT THAT IS IDENTIFIABLE ON BOTH THE GROUND & THE MAP AND MARK THE MAP LOCATION.

43. STEP 5: MEASURE THE MAGNETIC AZIMUTH (w/ your Compass) TO THE SECOND KNOWN POSITION & CONVERT THE MAGNETIC AZIMUTH TO A GRID AZIMUTH.
151 DEGREES
MAGNETIC

44. MAGNETIC AZIMUTH: 151 DEGREES
STEP 5: MEASURE THE MAGNETIC AZIMUTH TO THE SECOND KNOWN POSITION & CONVERT THE MAGNETIC AZIMUTH TO A GRID AZIMUTH.
MAGNETIC AZIMUTH: 151 DEGREES
EASTERLY G-M ANGLE: +21 DEGREES
GRID AZIMUTH: DEGREES

45. GRID BACK AZIMUTH: 352 DEGREES
STEP 6: CHANGE THE GRID AZIMUTH TO A BACK AZIMUTH & DRAW A LINE FROM THE SECOND KNOWN POSITION BACKWARD TOWARD YOUR UNKNOWN POSITION.
GRID AZIMUTH: DEGREES
ADD: DEGREES
GRID BACK AZIMUTH: DEGREES

46. 352 STEP 6. CHANGE THE GRID AZIMUTH TO A BACK
AZIMUTH AND DRAW A LINE FROM THE
SECOND KNOWN POSITION BACKWARD
TOWARD YOUR UNKNOWN POSITION.
KP 1
352
KP 2

47. STEP 7: THE POINT WHERE THE 2 LINES INTERSECT IS YOUR LOCATION.
KP 1 EG
KP 2

48. STEP 8: FOR A CHECK ON ACCURACY, YOU SHOULD
CONSTRUCT A THIRD LINE FOLLOWING THE
STEPS AS OUTLINED.
KP 1
KP 3
KP 2
WHENEVER POSSIBLE, CHOOSE LOCATIONS THAT WILL GIVE YOU A LARGER ANGLE WHERE THE LINES
INTERSECT TO INCREASE ACCURACY.

49. Practical Exercise 1 of 2
WHILE ON A RECONNAISSANCE MISSION, AN ENEMY SCOUT PLATOON DETECTS YOUR SQUAD. YOU TAKE UP A DEFENSIVE POSITION & DECIDE TO REQUEST INDIRECT FIRE SUPPORT. YOU ARE NOT SURE OF YOUR LOCTION. FROM YOUR LOCATION, YOU CAN SEE A LOOKOUT TOWER IN GRID EG 1887 AT A MAGNETIC AZIMUTH OF 110 DEGREES & A TV RELAY TOWER IN GRID EG1287 AT A MAGNETIC AZIMUTH OF 215 DEGREES.
QUESTION: WHAT IS YOUR LOCATION?
ANSWER: EG
YOU DETERMINE A DISTANCE OF 800 METERS TO THE ENEMY
WITH YOUR LASER RANGE FINDER AND A MAGNETIC AZIMUTH OF
290 DEGREES.
QUESTION: WHAT IS THE GRID LOCATION OF THE ENEMY SCOUT
PLATOON?
ANSWER: EG

50. Practical Exercise 2 of 2
QUESTION: YOU HAVE DETERMINED THAT THE MAGNETIC AZIMUTH FROM YOUR POSITION TO THE TV RELAY TOWER IN GRID SQUARE EG1287 IS 3 DEGREES & THE MAGNETIC AZIMUTH TO THE SPOT ELEVATION 199 IN GRID SQUARE EG 1385 IS 77 DEGREES. WHAT IS THE SIX DIGIT GRID COORDINATE OF YOUR LOCATION?
ANSWER: EG
QUESTION: THE MAGNETIC AZIMUTH FROM YOUR LOCATION TO THE
WATER TOWER AT EG IS 63 DEGREES AND THE
MAGNETIC AZIMUTH TO THE WATER TOWER AT EG097827
IS 104 DEGREES. WHAT IS THE SIX DIGIT COORDINATE TO
YOUR LOCATION?
ANSWER: EG

51. Summary Purpose Polar Coordinates & Practical Exercise
Intersection & Practical Exercise
Resection & Practical Exercise
Summary
Conclusion

52. Conclusion
Advanced land navigations techniques such as polar coordinates, intersection, and resection are essential to navigating successfully and accurately. Having theses skills will help you fight, survive, and win on the battlefield.