Section 117

Question 1

What are the 12 parts of the lensatic compass?

Answer 1

1. Luminous Sighting Dots
2. Sighting Wire
3. Luminous Magnetic Arrow
4. Short Luminous Line
5. Fixed Index Line
6. Graduated Straight Edge
7. Sighting Slot
8. Lens
9. Thumb Loop
10. Floating Dial
11. Bezel Ring
12. Lens or Rear Sight

Question 2

Discuss the map feature identified by RED.

Answer 2

Classifies cultural features, such as populated areas, main roads, and boundaries, on older maps.

Question 3

Discuss the map feature identified by BLUE

Answer 3

Identifies hydrography or water features such as lakes, swamps, rivers or drainage.

Question 4

Discuss the map feature identified by RED BROWN.

Answer 4

Red and brown combined on red-light readable maps to identify cultural features, all relief features, non-surveyed spot elevations, and elevations such as contour lines.

Question 5

Discuss the map feature identified by BLACK

Answer 5

Indicated cultural (man-made) features such as buildings and roads

Question 6

Discuss the map feature identified by BROWN.

Answer 6

Identifies all relief features and elevations, such as contours on older edition maps, and cultivated land on red-light readable maps.

Question 7

Discuss the map features using a standard 1:50,000 military map: HILL

Answer 7

Hill is an area of high ground. Hill is shown on a map by contour lines forming concentric circles. Inside of the smallest closed circle is the hilltop.

Question 8

Discuss the map features using a standard 1:50,000 military map: SADDLE

Answer 8

Saddle is a dip or low point between two areas of higher ground. May be a dip/break along a level ridge crest. A saddle is normally represented as an hourglass.

Question 9

Discuss the map features using a standard 1:50,000 military map: RIDGE

Answer 9

Ridge is sloping line of high ground. Standing on a ridge you will have low ground in 3 directions and high ground in 1. Contour lines forming a ridge tend to be C-Shaped or V-Shaped. Closed end of the contour line points away from high ground

Question 10

Discuss the map features using a standard 1:50,000 military map: DEPRESSION

Answer 10

A low point in the ground or sinkhole. It could be described as an area of low ground surrounded by higher ground in all directions. Represented by closed contour lines that have tick marks pointing toward low ground.

Question 11

Discuss the map features using a standard 1:50,000 military map: FINGER (SPUR)

Answer 11

Spur is a short, continuous sloping line of higher ground, normally jutting out from the side of a ridge. A spur is often formed by two rough parallel streams, which cut draws down the side of a ridge.

Question 12

Discuss the map features using a standard 1:50,000 military map: DRAW

Answer 12

Draw is a less developed stream course than a valley. If you are standing in a draw, the ground slopes upward in 3 directions and downward in the other. Draw could be considered as the initial formation of a valley. The contour lines depicting a draw are U-Shaped or V-Shaped, pointing toward high ground.

Question 13

Explain what a grid azimuth is.

Answer 13

When and azimuth is plotted on a map between point A (starting point) and point B (ending point). Points are joined together by a straight line. Protractor is used to determine angle between grid North and drawn line.

Question 14

Explain what a magnetic azimuth is.

Answer 14

Determined by using magnetic instruments, such as lensatic and M2 compass.

Question 15

Explain what a back azimuth is.

Answer 15

The opposite direction of an azimuth. It is comparable to doing “about face” To obtain a back azimuth from an azimuth, add 180 degrees if the azimuth is 180. The back azimuth of 180 can be stated as 0 or 360.

Question 16

Discuss or show True North.

Answer 16

A line from any point on the earth’s surface to the North Pole. All lines of longitude are true north lines. True north is usually represented by a star.

Question 17

Discuss or show magnetic north.

Answer 17

Direction to the north magnetic pole, as indicated by the north-seeking needle of a magnetic instrument. The magnetic north is usually symbolized by a line ending with half of an arrowhead. Magnetic readings are obtained with magnetic instruments

Question 18

Discuss or show Grid North.

Answer 18

North that is established by using he vertical grid lines on the map. Grid north may be symbolized by the letters GN or the letter “y”

Question 19

Discuss the techniques used to orient a map using a Compass.

Answer 19

Compass measures magnetic north. With map in horizontal position, take the straightedge on the left side of the compass and place it along the magnetic north arrow on the declination diagram with the cover of the compass pointing toward the top of the map. This procedure places the fixed black index line of the compass parallel to the magnetic north arrow. Keeping the compass aligned as directed, rotate the map and compass together until the arrows line up.

Question 20

Discuss the techniques used to orient a map using Terrain Association.

Answer 20

Use this method when a compass is unavailable. Identify prominent terrain features on the map that you can find on the ground. Align terrain features with the map. If there is a tower to your front, then orient the map so that the tower is to your right front. If there is a road to your left, ensure the road on the map is parallel. Once all features are lined up, your map is oriented.

Question 21

Discuss the procedure for determining the location of an unknown point by intersection.

Answer 21

Intersection is the location of an unknown point by successfully occupying at least two or three known positions on the ground and then map sighting on the unknown location. It is used to locate distant or inaccessible points or objects such as enemy targets and danger areas. There are two methods of intersections: The map and compass method The straightedge method.