75th Ranger Regiment

For the benefit of some of the aspiring members of the Special Operations community, we’ve been going back to the basics of passing Land Navigation. This was after a recent article that stated the Army has noticed a lack of expertise at junior NCOs with a map and compass.

Waiting until one gets to Selection isn’t the time to learn that your Land Navigation skills are not up to snuff and will result in a very long face especially in SFAS once you experience the loveliness of Hoffman. As we mentioned in our piece last week three of the biggest issues that stop candidates from being selected are Physical Fitness Preparation, Rucking, and Land Navigation.

SFAS will combine all three of those issues in the very early days of the course, as candidates will be running for time, rucking and then join the three into the Land Navigation course, known as the Star Course in Hoffman.

Today, we are going to look at the way to find your location if you are unsure of your exact map placement. And before you say “I’ll never get lost that way!” I’ll say this, ‘wait until you get there first.’ There is going to be times in the course that you won’t be certain of your exact location. If you are unsure of your exact location, you can find your location easily if you can pick out some distant landmarks. It is called Resection.

Resection is defined as the method for finding your exact location on a map by determining the grid azimuth to two or more 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.

For the purposes of our practical application, we used only two however, obviously, three or more is ideal. There are three methods of using resection, using the map and compass method, the straightedge method and the modified method. In this exercise, we used the map and compass method, but we’ll go over the other methods as well.

Map and Compass Method

•         Orient the map using the compass and terrain association
•         Identify two or three known distant locations on the ground and mark them on the map.
•         Measure the magnetic azimuth to one of the known positions from your location using a compass.
•         Convert the magnetic azimuth to a grid azimuth.
•         Convert the grid azimuth to a back azimuth. If the magnetic azimuth is less than 180 degrees add 180. If the azimuth is more than 180 degrees subtract 180.
•         Using a protractor, draw a line for the back azimuth on the map from the known position back toward your unknown position.
•         Repeat the same steps for a second position and a third position if desired.

The intersection of the lines is your location. Determine the grid coordinates to the desired accuracy, an eight-digit grid being the preferred accuracy for our purposes.

Straightedge Method:

To accurately find your position, the successful navigator must:

•         Orient his map using his compass and/or terrain association
•         Locate at least two known distant locations or prominent features on the ground and mark them on the map.
•         Lay a straightedge on the map, in this case using the compass and a known position as a pivot point.
•         Rotate the straightedge until the known position on the map is aligned with the known position on the ground.
•         Draw a line along the straightedge away from the known position on the ground toward your position.
•         Repeat the same process using a second known position that you can see from your location.

Where the intersection of the lines meets on the map is your location. Determine the grid coordinates to the desired accuracy. You then should be able to get an eight-digit grid coordinate and find your way to your point.

Modified Method:

The modified method is the least preferred method but is useful in certain situations. If you’re not certain of your exact location but are located on a linear terrain feature such as a road, creek or similar body of water, this can pinpoint your position.

• Orient the map using a compass and/or by terrain association.
• Locate a point in the distance that can be easily identified on the ground and on the map.
• Determine the magnetic azimuth from your location to the distant known point.
• Convert the magnetic azimuth to a grid azimuth.
• Convert the grid azimuth to a back azimuth, using the add or subtract 180 accordingly depending on the degrees.
• Using a protractor, draw a line for the back azimuth on the map from the known position back toward your unknown position.

Your location is where the line on the map crosses the linear feature. Determine the grid coordinates to the desired accuracy, for our purposes an eight-digit grid coordinate.

For our video demonstration, practical exercise, we were moving along our azimuth and came across a railroad track. Just barely visible in the far distance is a wind turbine that sits high upon a hilltop. Once we are able to locate the wind turbine on the map, we take an azimuth, using our compass, and determine the grid azimuth.

Then we draw a back azimuth using the “more than 180 degrees subtract 180 or less than 180 degrees add 180” rule and draw a line on our map. Where the line intersects the railroad line is our exact location.

If this were close to our point during a Land Navigation course, this would be a prime attack point as you’d have a very good place to search for the point. However, if you’re still far from your point, it is a great place to check your exact location and ensure that you’re heading on the correct azimuth.

Check out the short video from two years ago and see how it works out. If anyone has any questions, feel free to email me [email protected] or at my Twitter account @SteveB7SFG

Photos courtesy of DOD, Video: Author