Section 117 Land Nav Flashcards
Name the 12 Parts of the Lensatic Compass
- Luminous Sighting Dots
- Fixed Index line
- Sighting Wire
- Graduated Straight Edge
- Luminous Magnetic Arrow
- Short Luminous Line
- Lens
- Sighting Slot
- Floating Dial
- Bezel Ring
- Lens or rear sight
- Thumb loop
What is a declination diagram
Shows relationships between True North, Magnetic North, and Grid North
What is the Bar Scale on a mpa
Rulers used to convert map distance to ground distance for different units of measure
What is an index contour line
Every fifth contour line which is heavier and numbered
What is an intermediate contour line
Fall between index contour lines, finer than index lines
What are supplementary contour lines
Resemble dashed line, usually represent half the change of contour lines and usually only shown where there is little elevation change.
What size boxes do 6, 8, 10 digit grids correspond to
6 Digit: 100m squared
8 Digit: 10m squared
10 Digit: 1m squared
What map features are red
Cultural (manmade) features, populated areas, main roads
What map features are blue
Hydrography, water features
What map features are black
Denotes buildings, roads, surveyed spot elevations and labels
What map features are brown
Relief features and elevation, cultivated land on red-light readable maps
What map features are red brown
Combined on red light readable maps to identify cultural features, relief features, and elevations
What map features are green
Vegetation with military significance such as woods, orchards, vinyards
What does a hill look like on a map
Think Target
What does a Saddle look like on a map
Think Boobies
What does a valley look like on a map
usually surrounded on 3 sides by high ground, usually has water running through it, contour lines form a U or V
What does a depression look like on a map
Closed contour lines (circle) with hash marks
What do draws/fingers look like on a map
- Draw, initial formation of a valley, U or V points to higher ground.
- Finger, U or V points away from higher ground
What does a cliff look like on a map
Converging countour lines may have hashes pointing off the edge
What does a cut look like on a map
Manmade, parallel lines with hash marks pointing to center
What does a fill look like on a map
Manmade, parrallel lines with hash marks pointing out from center
What is True North
Line pointing to the North pole, all longitude lines point to true north, usually represented by a star
What is Magnetic North
The direction to the Magnetic North Pole, indicated by the North seeking magnetic needle of a compass, Line ends with a half arrowhead
What is Grid North
Established using vertical lines on a map, usually marked by letters “GN” or “Y”
How many Mils in 360 degrees
6400 mils
What is an azimuth
Horizontal angle measured clockwise from a north base line (may be true, magnetic, or grid)
What is a back Azimuth
“About face” Add or subtract 180 degrees depending on starting value.
What is a grid azimuth
Calculated on a map, must be converted to magnetic to use compass
How do you remember to add or subtract when going Grid to magnetic or vice versa
Major to General ADD (Mag to Grid = add)
General to Major SUBTRACT (Grid to Mag = Subtr)
