Finding Your Position (MGRS)

Resection

To locate your position when you do not know exactly where you are, orient your map as closely as possible by using one of the methods previously mentioned.

Next, look for a feature such as the water tower (A) that you can find on the map. Put a ruler or straightedge on the map, and place its edge right next to the water tower symbol (B) on the map. Then align the straightedge so that it points exactly at the real water tower. Draw a line along the ruler (the line will cross the water tower symbol on the map).

Find another feature such as the road junction (C), and do the same thing. When you lay the straightedge on your map and point it at the real road junction, its edge crosses over the road junction on the map (D). Draw another line along the ruler until it crosses (intersects) the first line. The point where the lines intersect is your location. This is called “resection.” A third line may help locate your position more accurately. Remember not to move your map once you have it properly oriented.

navigation_finding_position_water_tower

Modified Resection

navigation_calculating_azimuths_01If you know that you are located somewhere along a certain linear feature on the map such as a road or riverbank, then you can use an easier method to pinpoint your location—a method called “modified resection.”

First, orient your map. Then locate a feature that you can also find on the map, such as the water tower in the previous example. Just as before, put a straightedge through the water tower symbol on the map and align the straightedge so that it points exactly at the real water tower. Draw a line along the ruler. The point where the line crosses the linear feature you are on is your location. If you do not have a regular straightedge, use your rifle’s cleaning rod, a section of radio antenna, or even the edge of a C-ration box.

NOTE: Always orient your map as closely as you can—using your compass is the best way.

The image to the right shows another way of using resection and modified resection to locate your position even closer than what you have just learned.

First, using your compass, shoot azimuths to your reference points, such as the water tower and the road junction. Next, convert the magnetic azimuths to grid azimuths, then determine the grid back azimuths and plot them on your map.

Your position is where these grid back azimuths intersect.

Intersection

Suppose you want to find the location of a certain object that you can see in the distance, such as an observation post (OP), but it is not on your map. First, shoot an azimuth to the object using your compass. If you have to, convert the magnetic azimuth to a grid azimuth. Next, draw a line on the map from your location along the grid azimuth that you came up with. The OP lies somewhere along this line.

To find out where, move to another location where you can observe the same OP or have another friendly element located somewhere else (who also sees the OP) shoot an azimuth to it.

As before, convert the azimuth from magnetic to grid and draw it on your map (out from the point where the azimuth was taken). The OP lies where the second line intersects with the first line. This method is called “intersection.”

navigation_intersection_process

 

[Continue to Determining Relief and Elevation]

**Information adapted from the United States
(U.S.) Army Training Support Centers (TSCs)
Graphic Training Aid (GTA) GTA 05-02-013,
How To Avoid Getting Lost.