Army Land Navigation Flashcards

Basic Map Colors and Their Meanings

• Black: Represents man-made features.
• Red-brown: Indicates cultural features and relief features, including contour lines.
• Blue: Depicts water features.
• Brown: Shows relief features.
• Red: Highlights population areas, main roads, and boundaries.

Map Legend

• Located in the lower left corner of the map.

Contour Lines

• Imaginary lines that connect points of equal elevation, used to represent high and low elevations.

Types of Contour Lines

• Index: The primary contour lines, typically labeled with elevation values.
• Intermediate: Lines between index lines, not labeled but provide detail.
• Supplementary: Often dotted or dashed, indicating additional elevation detail.

Measurement and Angles

• 1 degree equals 17.7 mils.
• A complete circle is 6400 mils.

North Directions on Military Maps

• True North: Based on Earth's geographic poles.
• Magnetic North: The direction a compass points.
• Grid North: Based on the vertical grid lines on maps.

Major Terrain Features

• Hill: Elevated ground.
• Valley: Low area between hills.
• Ridge: Long, narrow elevated land.
• Saddle: A dip in a ridge.
• Depression: Lower area on the terrain.

Minor Terrain Features

• Draw: A small, narrow valley.
• Spur: A projection or point of higher ground.
• Cliff: Steep vertical or near-vertical rock face.

Supplementary Features

• Cut: Feature where earth has been removed.
• Fill: Earth that is added to raise elevation.

Map Definition

• A graphical representation of a portion of the Earth's surface, depicted from an aerial viewpoint and drawn to scale.

Azimuth

• A horizontal angle measured clockwise from a north baseline, indicating direction.

Vertical Distance

• The distance between the highest and lowest points.

Grid Lines

• Distance between grid lines on a military map is 1 kilometer.

Map and Compass Usage

• Grid north is used with maps, while magnetic north is utilized with compasses.
• Two methods to hold a compass: Compass-to-cheek and Center-hold.

Map Overlays Colors

• Blue: Friendly forces.
• Red: Enemy forces.
• Black: Boundaries.
• Yellow: Contaminated areas.
• Green: Engineer obstacles.

Back Azimuth

• The direction opposite to an azimuth.

Declination Diagram

• Illustrates the angular relationship between magnetic, grid, and true north.

Military Grid Coordinates

• Read coordinates by moving right and up.

Benchmark

• A man-made marker indicating elevation points.

Lensatic Compass Bezel Ring

• Each click of the bezel ring corresponds to 3 degrees.

Map Orientation

• Can be oriented using a compass or terrain association.

FLOT

• Acronym for Forward Line of Troops.

Intersection

• Locating a point using the intersection of two azimuths.

Resection

• Determining location using back azimuths from two known points.

Map Quadrants

• Divided into Northeast, Northwest, Southeast, and Southwest quadrants.

Dead Reckoning

• Requires a known starting point, known distance, and known azimuth.

Polar Coordinates

• Plotting utilizes an azimuth and distance from a known starting point.

Neat Line

• The border line surrounding the edge of the map.

Contour Level

• Vertical distance between contour lines, found in marginal information.

Types of Slopes

• Gentile: Gradual slope.
• Steep: Sharp incline.
• Concave: Curves inward.
• Convex: Curves outward.

Grid Accuracy

• An 8-digit grid provides accuracy to 10 meters.
• A 6-digit grid provides accuracy to 100 meters.

Measuring Ground Distance on a Map

• Use a bar scale for measuring actual distances.

Military Geographic Acronyms

• MGRS: Military Grid Reference System.
• UTM: Universal Transverse Mercator.
• UPS: Universal Polar Stereographic.