Map Colors
Black -cultural man made features (bldgs, roads, elevations, all labels) Blue -hydrography or water features (stream, river, lake, swamp, etc) Green -vegetation w/ military significance (woods, orchards, vineyards, etc) Red /Brown -combined to ID cultural features, all relief features, elevation, and contour lines (used on newer red light readable maps)
Major Terrain Features
Hill
Saddle
Valley
Ridge
Depression
Minor Terrain Features
Draw
Spur
Cliff
Supplementary Terrain Features
Cut & Fill CUT FILL
Military Grid Reference System
VGT 20A 1000 Meter Grid Square
VGT 21
1000 Meters
90 03 FT Digit Grid – within 1000m
Placement of Coordinate Scale on a Grid
100 Meter s FT Digit Grid – within 100 m
100 Meter s FT Digit Grid – within 100 m
100 Meter s Digit Grid – within 10 m
Digit Grid – within 10 m FT
8 Digit Grid – within 10 m FT
(1:50,000 scale Tenino map) 1) Find an 8 digit grid for Crawford Mountain Lookout Tower (vic EG 1887). Answer: EG ) What structure is located at EH ? Answer: Abandoned Machine Gun Bunker Railroad Bridge Practical Exercise 2) Find an 8 digit grid for the Zion Chapel (vic EH 1102). Answer: EH ) What structure is located at EG ? Answer: 5) What is the terrain/vegetation like vicinity of EG ? Answer: Marsh / swamp
Measuring Distance
Contour Lines
Graphic Scale Statute Miles Kilometer s Nautical Miles
Straight Line Distance
Curved Line Distance
1) What is the straight line distance (in meters) between the Olympia Municipal Airport Beacon (EH ) and the horizontal control station located at EG ? Answer: 4,970 m 4) What is the road distance in meters from EG to EH ? Answer: 5,150 m (approx) Practical Exercise – Horizontal Distance 2) What is the straight line distance (in meters) between the chimney located at EG and the water tower located at EG ? Answer: 4,360 m 3) What is the straight line distance (in meters) between Violet Prairie Church (vic EG 0687) and the water tower located vic EG 1088? Answer: 4,390 m
1) What is the vertical height (in meters) at EG ? Answer: 120 m Practical Exercise – Vertical Distance 2) What is the change in vertical distance from EG to EG ? Answer: 220 m ; (360m – 140m) 3) What is the estimated maximum elevation of the hilltop located at EG ? Answer: 310 m
Grid Azimuth
VGT 28
VGT 23
VGT 30 A B
VGT 31 A B
1) What is the back azimuth of 71 degrees? Answer: 251 degrees 3) What is the Grid Azimuth from the TV Relay Tower (EG ) and the water tower near Forest Cemetary (EG )? Answer: 206 degrees Practical Exercise 2) What is the back azimuth of 287 degrees? Answer: 107 degrees
Your Magnetic Compass
VGT 43
VGT 44
Compass to Cheek Method
Centerhold Method
Angle Conversion
VGT 32 THREE NORTH'S TRUE NORTHMAGNETIC NORTHGRID NORTH G N N
VGT 33
MN X X = GM Angle Magnetic to Grid (M G): Add Easterly Rules Grid to Magnetic (G M): Subtract
X MN Magnetic to Grid (M G): Subtract Westerly Rules Grid to Magnetic (G M): Add X = GM Angle
Convert the following from grid azimuth to magnetic azimuth. 1) Grid Az – 131, G-M Angle – 13 east, Mag Az – 2) Grid Az – 299, G-M Angle – 11 west, Mag Az – 3) Grid Az – 035, G-M Angle – 04 west, Mag Az – Practical Exercise 118 degrees mag 310 degrees mag 039 degrees mag Convert the following from magnetic azimuth to grid azimuth. 1) Mag Az – 008, G-M Angle – 09 east, Grid Az – 2) Mag Az – 213, G-M Angle – 18 east, Grid Az – 3) Mag Az – 077, G-M Angle – 21 west, Grid Az – 017 degrees grid 231 degrees grid 056 degrees grid
Slope
% slope = Vertical Distance (VD) x 100 Horizontal Distance (HD) b a VD = Elevation at b – Elevation at a HD = Straight line distance between a & b VD Percent Slope HD
Degree slope = Vertical Distance (VD) x 57.3 Horizontal Distance (HD) b a VD = Elevation at b – Elevation at a HD = Straight line distance between a & b VD Degree Slope HD
Intersection
We have two OPs located in front of our defensive position. Both OPs can see enemy activity. From OP1, the enemy activity is 32-degrees magnetic and from OP2, it is 322 degrees magnetic. The G-M angle is 18-degrees easterly. The magnetic azimuth from OP1 is 32 degrees. Convert this to a grid azimuth by adding the 18-degree G-M angle. The grid azimuth would be 50 degrees. Using the protractor, plot this azimuth on the map. Convert the 322-degree magnetic azimuth to a grid azimuth. the grid azimuth is 340 degrees. Using the protractor, plot this azimuth. The enemy is located where the line cross. Intersection
Step 2: -Convert azimuth from magnetic to grid G-M Angle: 18 east OP1: 032 magnetic = 050 grid OP2: 322 magnetic = 140 grid Step 1: -Identify / plot OPs or points of reference
Step 3: - Plot first azimuth (050 degrees grid)
Step 3: - Plot first azimuth (050 degrees grid) Step 4: - Plot second azimuth (240 degrees grid)
Bad Guys Step 3: - Plot first azimuth (050 degrees grid) Step 4: - Plot second azimuth (240 degrees grid) Step 5: - Plot intersection
Bye Bye Step 3: - Plot first azimuth (050 degrees grid) Step 4: - Plot second azimuth (240 degrees grid) Step 5: - Plot intersection Step 6: - Kill Bad Guys
Resection
Looking out from our position we can see a bridge. We determine the magnetic azimuth to its location to be 159 degrees. For the purpose of this problem, assume that there is a 1-degree westerly G-M angle. Convert from magnetic giving you a grid azimuth of 158 degrees. Next, we must convert this grid azimuth to a BACK azimuth by ADDING 180 degrees and plot the back azimuth of 338 degrees from the bridge. Our location is somewhere along this line. From our location, we can also see a larger road intersection. the road intersection is on a magnetic azimuth of 117 degrees. The grid azimuth is 116 degrees. Back Azimuth of 296 degrees g. The back azimuth of 296 degrees is plotted from the road intersection. Your location is where the lines cross.
Step 2: -Convert azimuth from magnetic to grid G-M Angle: 01 west Bridge: 159 magnetic = 158 grid Road Int: 117 magnetic = 116 grid Step 1: -Identify / plot OPs or points of reference
Step 3: -Convert azimuth to back azimuth G-M Angle: 01 west Bridge: 158 grid from you Back Az: = 338 Road Int: 116 grid from you Back Az: = 296
Step 4: - Plot first back azimuth from landmark (bridge)
Step 4: - Plot first back azimuth from landmark (bridge) Step 5: - Plot second back azimuth from landmark (road intersection)
X Step 4: - Plot first back azimuth from landmark (bridge) Step 5: - Plot second back azimuth from landmark (road intersection) Step 6: - Plot your position
X Step 4: - Plot first back azimuth from landmark (bridge) Step 5: - Plot second back azimuth from landmark (road intersection) Step 6: - Plot your position Step 7: - Move out to chow
Modified Resection
Looking out from our position along Steam Mill Road, we can see the top of Hill 445 to our NW. We determine the magnetic azimuth to its location to be 299 degrees. For the purpose of this problem, assume that there is a 18- degree easterly G-M angle. Convert from magnetic giving you a grid azimuth of 317 degrees. Convert and plot the back azimuth of 137 degrees. Our location along Steam Mill Road is where this line crosses the road.
Step 2: - Convert azimuth from magnetic to grid G-M Angle: 18 east OP1: 299 magnetic = 317 grid Step 1: -Identify / plot OPs or points of reference Step 3: - Convert azimuth to back azimuth Hill 445: 317 grid from you Back Az: = 137
Step 4: - Plot back azimuth from landmark (Hill 445)
X Step 4: - Plot back azimuth from landmark (Hill 445) Step 5: - Plot your position where the line intersects the road you are on Step 6: - Drive on airborne, START WALKING!!
Solve the following problem by intersection. You receive radio calls from both OP1 and OP2. Each report enemy activity to their south. Both report approx 5 dismounted troops and one vehicle. You believe they are looking at the same enemy unit. If you can determine their location, you can destroy them with artillery fires. OP1, located atop Hill 210 vic EG1290, reports the enemy to be at 100 degrees magnetic from his location. OP2, located atop Hill 222 vic EG1690, reports the enemy to be at 168 degrees magnetic from his location. What is the 8 digit grid to the enemy? Answer - Practical Exercise - Intersection EG
Questions?
Example: 9 Easterly Rules Magnetic to Grid (M G): Add 000 G 009 G or 000 M 216 mag + 9 = 225 grid M 225 G Mag Az = 216 GM Angle = 9 east
Example: Grid Az = 026 GM Angle = 17 east Easterly Rules 000 G 026 grid - 17 = 9 grid Grid to Magnetic (G M): Subtract 017 G or 000 M 026 G or 009 M 9 17
Example: Mag Az = 286 GM Angle = 17 west Westerly Rules Magnetic to Grid (M G): Subtract 286 mag - 17 = 269 grid 000 G 286 M or 269 G 17
Westerly Rules Grid to Magnetic (G M): Add 000 G G or 124 M Example: Grid Az = 112 GM Angle = 12 west 112 grid + 12 = 124 mag
Terrain Features 1)_____________ 2)_____________ 3)_____________ 4)_____________ 5)_____________ 6)_____________ 7)_____________ 8)_____________ 9)_____________ 10)_____________
Terrain Features