CH. 114 Land Navigation Fundamentals Flashcards
What is a Sheet Name on a map?
-Named after the most prominent cultural or geographical feature.
EX. largest city on the map is used
-Found on map: center of the upper margin and right or left side of the lower margin
What is a Sheet Number and Where is it located?
- The reference number of that map
- Upper right margin/Lower left margin
What is a Map Scale on a map?
- Representative fraction that provide a ration of distance on the map to distance corresponding on the Earth’s surface.
- 1:50,000 is less detail than 1:25,000 on a map
What is the Elevation Guide on a map?
- Miniature characterization of the terrain shown
- Helps you rapidly identify major land forms
- Found in the lower margin
What is a Declination Diagram on a map?
- Angular relationship to true north,grid north, and magnetic north
- Located in lower margin
What is a Bar Scale on a map?
- Converts map distance to ground distance
- Located in center of the lower margin
What does a Legend on a map do?
- Illustrates and identifies the topographic symbols used to depict prominent features
- EX: railroad tracks, buildings, swamps, etc
- Located lower left margin
What are Grid Lines on a map?
- Straight lines intersecting at right angles horizontal and vertical grid lines.
- Principal digits: # used most often for reference points. Large type at each end of the grid line
What is the Basic Map Reading rule?
-Read right than up,read right on vertical line then up on the horizontal line
A four digit grid coordinate will locate a point on a map within how many meters?
1,000 square meters
A six digit grid coordinate will locate a point on a map within how many meters?
100 square meters
A eight digit grid coordinate will locate a point on a map within how many meters?
10 square meters
What is True North?
- Any point on the Earth’s surface to the North Pole
- Located by the North Star
What is Magnetic North?
- Magnetic field that is close to (but not exactly on) the North Pole
- North seeking arrow of your lensatic compass
What is Grid North?
- Vertical lines on a map representing north
- Letters GN
What are the 5 primary terrain features on a map?
-Hill, Saddle, Ridge, Finger/Spur, Draw
What are the 3 supplemental terrain features on a map?
-Valley, Cliff, and Depressions
What are the 2 man made features on a map?
-Cuts and Fills
Identify the parts of a Lensatic Compass?
-Cover,Base,Floating Dial,Glass Encasement, Bezel Ring, Lens, Rear sight slot
How many degrees are in a compass?
360
How many mils are in a compass?
6400
How many mils are in 1 degree?
17.78
What does the acronym KOCOA mean?
-Key terrain, Observation, Cover and Concealment, Obstacles and Avenues of Approach
What are Grid Squares?
- Lines intersecting at right angles horizontal and vertical grid lines
- measures in 1,000 meters x 1,000 meters
Describe a Saddle feature on a map?
- Saddle (series of hills connected to each other near the top)
- Represented as an hourglass or figure-eight shape
Describe a Hill feature on a map?
- Hill (area on high ground)
- Shown on a map by contour lines forming a concentric circles.
- Inside of the smallest closed circle is the hilltop
Describe a Ridge feature on a map?
-Ridge (dip or lower b/w 2 areas of higher ground)
Describe a Finger/Spur feature on a map?
- Finger/Spur (sloping line of higher ground: ridge or hill)
- Depicts a finger with a U or V pointing away from higher ground
Describe a Draw feature on a map?
- Draw (short,continuous sloping line low ground, cut into the side of ridge or hill)
- Depicts a finger with a U or V pointing toward higher ground
Describe a Depression feature on a map?
- Depression (low point of sinkhole in the ground)
- Represented by closed contour lines that have tick marks pointing towards low ground
What is the Cover in a lensatic compass?
- Protects the floating dial and glass encasement.
- Contains the sighting wire and 2 luminous sighting dots for night navigation
What is the Base in a lensatic compass?
-4 parts: Floating Dial, Glass Encasement, Bezel Ring, and Thumb Loop
Describe the Floating Lens?
-Floating Dial (mounted on a pivot, so it can rotate freely when held level)
: Luminous arrow and “E” and “W” are printed on dial.: Letters fall east (E) 90 degrees, and west (W) 270 degrees
-2 scales: outer denotes MILS (black); inner denotes (red)
Describe a Bezel Ring?
- Clicks when turned
- (1 click=3 degrees; 120 click =full rotation)
Describe the Thumb Loop?
-attacked to the base
What is the Rear Sight Slot of a lensatic compass?
-Used in conjunction w/ front sights wire when aiming at objects
How do u convect a Magnetic Azimuth to a Grid Azimuth?
-Add the G-M (Grid-Magnetic) angle
How do u orient a map using a Compass?
- (1) With the map flat on the ground; place a straightedge (left side of compass) along the magnetic north arrow on the declination diagram so that the cover of the compass is pointing towards the top of the map. This will put the fixed black index line of the compass parallel to the magnetic north arrow of the declination diagram.
(2) Keeping compass aligned; rotate the map and compass simultaneously until the north-seeking arrow is below the fixed black index line on the compass
How do u orient a map using Terrain Association?
- (1) Locate prominent terrain features on the map that u would fine on the ground
- (2) Align terrain feature w/ map
What are the 3 ways to determine your position?
-Location by Inspection, Location by One-Point Resection, and Location by Two-Point Resection
Describe Location by Inspection technique?
-By orienting the map by prominent features in the vicinity near where u are standing
Describe how to use the Location by One-Point Resection technique?
- (1) Identify a prominent feature on the ground and locate that feature on your map.
- (2) Using compass-to-check technique sight on the feature and read the magnetic azimuth
- (3) Convert the magnetic azimuth to a grid azimuth
- (4) Convert your grid azimuth to a grid back azimuth
- (5) with protractor, plot this grid back azimuth from the feature on the map and extend it until it crosses the linear feature
- (6) Conduct a map inspection of your resection
- (7) When selecting a terrain feature, choose on that is perpendicular to the axis of the linear terrian feature so that when you plot the back azimuth on the map, the line will cross the linear more of less in a right angle
Describe how to use a Location by Two-Point Resection technique?
- (1) Select 2 prominent features on the ground whose positions can be located on the map. Should be 30 degrees but not greater than 150 degrees apart
- (2) Use the check-to-check technique, determine magnetic azimuth to each object.
- (3) Convert these magnetic azimuths to grid back azimuths
- (4) With protractor, draw respective azimuths from these 2 points on your map.
- (5) Extend the azimuth lines from these 2 points until they intersect. u are located at the point where they meet
- (6) Conduct a map inspection to verify your posiotion
