Report Date: 071-COM-1011 Orient a Map Using a Lensatic ...

071-COM-1011 Orient a Map Using a Lensatic Compass

Status: Approved

Report Date: 19 Aug 2021

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Security Classification: U - Unclassified Distribution Restriction: Approved for public release; distribution is unlimited. Destruction Notice: None Foreign Disclosure: FD1 - This training product has been reviewed by the training developers in coordination with the G2, Ft Benning, GA 31905 foreign disclosure officer. This training product

can be used to instruct international military students from all approved countries without restrictions.

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Conditions: You are a member of a squad or team in a field environment and have been directed to orient a map in preparation for movement. You

have a 1:50,000-scale topographic map of the area and a compass. Some iterations of this task should be performed in MOPP 4.

Standards: Lay the map in a horizontal position, determine the direction and value of declination, and orient the map to the ground using a compass.

Special Conditions: None Safety Risk: Low MOPP 4: Sometimes

Cue: None

None

Task Statements

DANGER

WARNING

None

CAUTION

None

Remarks: None

Notes: The first step for a navigator in the field is orienting the map. A map is oriented when it is in a horizontal position with its north and south

corresponding to the north and south on the ground.

When orienting a map with a compass, remember that the compass measures magnetic azimuths. Since the magnetic arrow points to magnetic north, pay special attention to the declination diagram. Two techniques are used.

Special care should be taken when orienting your map with a compass. A small mistake can cause you to navigate in the wrong direction.

Once the map is oriented, magnetic azimuths are determined using the compass. Do not move the map from its oriented position since any change in its position moves it out of line with the magnetic north.

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1. Lay the map in a horizontal position.

Performance Steps

2. Determine the direction of the declination and its value from the declination diagram on the map.

3. Orient the map using of the following techniques: Note: There are two techniques that can be used to orient the map using a compass.

a. Orient the map using the first technique.

(1) Take the straightedge on the left side of the compass and place it alongside the north-south grid line with the cover of the compass pointing toward the top of the map.

Note: This procedure places the fixed black index line of the compass parallel to north-south grid lines of the map.

(2) Keep the compass aligned as directed above while rotating the map and compass together until the magnetic arrow is below the fixed black index line on the compass.

Note: At this time, the map is close to being oriented.

(3) Rotate the map and compass in the direction of the declination diagram.

(4) Verify the G-M angle.

(a) If the magnetic north arrow on the map is to the left of the grid north, check the compass reading to see if it equals the G-M angle given in the declination diagram (Figure 1).

Figure 1. Map oriented with 10 degrees west declination. Page 3

(b) If the magnetic north is to the right of grid north, check the compass reading to see if it equals 360 degrees minus the G-M angle (Figure 2).

Note: If the G-M angles are correct the map is oriented.

Figure 2. Map oriented with 21 degrees east declination. b. Orient the map using the second technique.

(1) Orient the map if the declination is easterly (right). Note: If the declination is easterly (right), the drawn line is equal to the value of the G-M angle. (a) Draw a magnetic azimuth equal to the G-M angle given in the declination diagram with the protractor using any north-south grid line on

the map as a base.

(b) Align the straightedge on the left side of the compass alongside the drawn line on the map. (c) Rotate the map and compass until the magnetic arrow of the compass is below the fixed black index line (Figure 3).

Note: The map is now oriented to grid north with the compass oriented to portray an eastern declination.

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Figure 3. Map oriented with 15 degrees east declination. (2) Orient the map if the declination is westerly (left).

Note: If the declination is westerly (left), the drawn line will equal 360 degrees minus the value of the G-M angle. (a) Determine the magnetic azimuth by subtracting the G-M angle given in the declination diagram by 360. (b) Draw the magnetic azimuth with the protractor using any north-south grid line on the map as a base. (c) Align the straightedge on the left side of the compass alongside the drawn line on the map. (d) Rotate the map and compass until the magnetic arrow of the compass is below the fixed black index line (Figure 4).

Note: The map is now oriented to grid north with the compass oriented to portray a westerly declination.

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