dcsimg
This website is not affiliated with the U.S. government or military.

Land Nav Task 15 - Determine Azimuths Using a Protractor

Standards: Determined the grid azimuth (in mils or degrees) from your location (point A) to point B to within 1 degree or 20 mils.

Conditions: Given a standard 1:50,000-scale military map with two known points plotted on the map, a protractor, a straightedge, a pencil, and requirement to determine the azimuth from your location (point A) to another point (point B) on the map.

Standards: Determined the grid azimuth (in mils or degrees) from your location (point A) to point B to within 1 degree or 20 mils.

 

Performance Steps

1.   The direction from one point to another, either on the map or on the ground, is called an azimuth. Azimuths are given in degrees or mils in a clockwise direction from north, and all azimuths taken from a map are grid azimuths.

a. An azimuth in degrees can be any number up to 360, as there are 360 degrees in a circle. Due east is 90 degrees, due south is 180 degrees, due west is 270 degrees, and due north is 360 degrees or 0 degrees.

b. An azimuth in mils can be any number up to 6400, as there are 6400 mils in circle. Due east is 1600 mils, due south is 3200 mils, due west is 4800 mils, and due north is 6400 mils or 0 mils.

2.   The most accurate way to determine an azimuth from a map is to use a protractor. There are two types of protractors in use in the Army today.

a. The square protractor (GTA 05-02-012), which has a degree scale and a mil scale. The inner scale is the degree scale, and the outer scale is the mil scale.

b. The semicircular protractor, which may or may not have two scales: an outer scale in mils and an inner scale in degrees. The mil and degree scales consist of two rows of numbers. In each of the scales, the outer row of numbers is used when determining azimuths to the east of your position, and the inner row of numbers is used when determining azimuths to the west of your position.

3.   Use the protractor properly.

a. Plot the location of two points on the map.

b. Using a straightedge, draw a straight line (azimuth line) from point A to point B.

Note.  The line drawn between the two points must be long enough to cross the scale(s) of the protractor in order to read the azimuth. Should the line between the two points be too short to cross the scale(s), extend the line beyond point B until it crosses the scale(s).

c.  Place the index of the protractor at the point where the azimuths line crosses one of the vertical (north-south) grid lines. This procedure allows greater accuracy in aligning the index line to a true reading where the azimuth line crosses the protractor scale.

Note. Ensure that the 0-degrees or 0-mils mark on the protractor is toward the top (north) of the map.

d. Start at the 0-degree or 0-mil mark on the protractor and read to the right (clockwise) until you reach the point where the azimuth line crosses the scale(s) of the protractor.

Note. When using the protractor, each tick mark on the degree scale is 1 degree, while each tick mark on the mil scale is 20 mils.

e. Read the azimuth where the azimuth line crosses the scale(s).

(1)  Figure 49, 65 degrees.

(2)  Figure 50, 65 degrees - 1150 mils.

Note. When using the square protractor, the scale can be read all the way around the protractor. In using the semicircular protractor, when point B is to the left (west) of point A. The protractor must be reversed so that 0 is toward the bottom of the map (south).

Evaluation Preparation: 

Setup: Provide the soldier with a 1:50,000-scale military map, two points plotted and labeled (A) and (B), a protractor, a straightedge, and a pencil.

Brief Soldier: Tell the soldier to determine the azimuth from point A to point B within one degree or 20 mils.

 

Performance Measures

GO

NO GO

1.   Determined the correct azimuth (within 1 degree or 20 mils).

--

--

Evaluation Guidance:  Score the soldier GO if the performance measure is passed. Score the soldier NO GO if the performance measure is failed. If the soldier scores NO GO, show what was done wrong and how to do it correctly.

References

 

Required

Related

 

FM 3-25.26

 

 

GTA 05-02-012