MAP READING AND LAND NAVIGATION FM 21-26
DEFINITION OF A MAP A MAP IS A GEOGRAPHIC REPRESENTATION OF A PORTION OF THE EARTH’S SURFACE DRAWN TO SCALE, AS SEEN FROM ABOVE. IT’S USES COLORS, SYMBOLS AND LABELS TO REPRESENT FEATURES FOUND ON THE GROUND.
PURPOSE OF A MAP A MAP PROVIDES INFORMATION ON THE EXSISTENCE OF, THE LOCATION OF, AND THE DISTANCES BETWEEN GROUND FEATURES. SUCH AS POPULATED PLACES ROUTES OF TRAVEL VARIATIONS IN TERRAIN HEIGHTS OF NATURAL FEATURES THE EXTENTOF VEGETATION COVER.
MAP SCALES LARGE: 1:50,000 MEDIUM: 1: 100,000 SMALL: 1: 250,000
COLORS OF THE MAP BLACK: MAN-MADE FEATURES, SUCH AS BUILDINGS AND ROADS. RED-BROWN: RELIEF FEATURES AND ELEVATION (CONTOUR LINES ON RED-LIGHT READABLE MAPS). BROWN: RELIEF FEATURES & ELEVATION (CONTOUR LINES ON OLDER MAPS). GREEN: VEGETATION (WOODS, ORCHARDS, VEGITATION). BLUE: DRAINAGE (WATER). RED: POPULATED AREAS, MAIN ROADS AND BOUNDARIES ON OLDER MAPS.
TERRAIN FEATURES Five Major Hidden Valley Ranch Salad Dressing Three Minor Two Supplementary Hidden Valley Ranch Salad Dressing Hilltop, Valley, Ridge, Saddle, Depression Draw, Spur, Cliff Cut, Fill
FM 21-26: PAGE 10-9 (FIGURE 10-17) HILL: AN AREA OF HIGH GROUND. FROM A HILLTOP, THE GROUND SLOPE DOWN IN ALL DIRECTIONS. FM 21-26: PAGE 10-9 (FIGURE 10-17) Contour lines forming concentric circles.
VALLEY: A STRETCHED-OUT GROOVE IN THE LAND, USUALLY FORMED BY STREAMS OR RIVERS. FM 21-26: PAGE 10-10 (FIGURE 10-19) Contour lines form U lines tend to parallel stream before crossing. Contour line crossing streams ALWAYS point up stream. Usually plenty of room to maneuver
RIDGE: A SLOPING LINE OF HIGH GROUND. FM 21-26: PAGE 10-11 (FIGURE 10-20) Contour lines forming a U or V; always point to high ground.
SADDLE: A DIP OR LOW POINT BETWEEN TWO AREAS OF HIGHER GROUND. FM 21-26 PAGE 10-11 (FIGURE 10-18) Between 2 hilltops or a break in the level crest of a ridge. Saddle usually appear as an hourglass
DEPRESSION: A LOW PO INT IN THE GROUND OR SINKHOLE. THEY ARE REPRESENTED BY CLOSE CONTOUR LINES THAT HAVE TICK MARKS POINTING TOWARD LOW GROUND. FM 21-26: PAGE 10-11 (FIGURE 10-21) In a depression there is higher ground on ALL sides
DRAW: A LESS DEVELOPED STEAM COURSE THAN A VALLEY. THERE IS ESSENTIALLY NO LEVEL GROUND AND, THEREFORE, LITTLE OR NO MANEUVER ROOM WITHIN ITS CONFINES. FM 21-26: PAGE 10-12 (FIGURE 10-22) Contour lines are V Shaped with the points of the V POINTING UPHILL and UPSTREAM
SPUR: A SHORT, CONTINUOUS SLOPING LINE OF HIGHER GROUND, NORMALLY JUTTING OUT FROM THE SIDE OF A RIDGE. FM 21-26: PAGE 10-12 (FIGURE 10-23) ususally formed by parrallel streams cutting down the side of a ridge Contour lines shaped like U or Vs point AWAY From HIGH GROUND
FM 21-26: PAGE 10-13 (FIGURE 10-24A & B) CLIFF: A VERTICAL OR NEAR VERTICAL FEATURE; IT IS AN ABRUPT CHANGE OF THE LAND. THE SLOPE IS SO STEEP THAT THE CONTOUR LINES CONVERGE INTO ONE CONTOUR LINE OR THE LAST CONTOUR LINE HAS TICK MARKS POINTING TO LOW GROUND. FM 21-26: PAGE 10-13 (FIGURE 10-24A & B)
CUT: A MAN-MADE FEATURE RESULTIING FROM CUTTING THROUGH RAISED GROUND, USUALLY TO FROM A LEVEL BED FOR A ROAD OR RAILROAD TRACK. FILL: A MAN-MADE FEATURE RESULTING FROM FILLING A LOW AREA, USUALLY TO FORM A LEVEL BED FOR A ROAD OR RAIL- ROAD TRACK.
STP21-1-SMCT PAGE 30 -31 (FIGURE4-5)
CONTOUR LINES 200 Three types of contour lines ELEVATION IN METERS Three types of contour lines Intermediate: Are contour lines located between two index lines. Supplementary: Are contour lines placed to specify half of the contour interval. EXAMPLE: CONTOUR INTERVAL 20 meters 100m 120m 130m and 140m SUPPLEMENTARY CONTOURS 10meters Index: Are major elevation points and have the elevation number written withing the contour. (ex.100m,200m,300m) 200
FINDING POINTS (Orient the map) (Compass Technique) (Grid Coordinates) Compass or Terrain Association (Compass Technique) Cheek and Center hold methods (Grid Coordinates) Grid Zone Designator (RP) and Number sequence FOUR DIGIT, SIX DIGIT or EIGHT DIGIT Remember RIGHT then UP DEAD RECKONING GRID ZN DESIG.... is the sheet ID
2 scales DEGREES which coorespond to the 360 deg of a compass and Mils 6400 1 degree = 17.7 mil
Compass Technique The compass to cheek technique is used almost exclusively for sighting and is the best technique for this purpose. COMPASS TO CHEEK METHOD CENTER HOLD METHOD METAL EFFECTS YOUR AZIMUTH UP TO 1 Meter away Advantages over CHEEK TECH Faster and easier Poor visibility Any type of terrain Do not need to put down your weapon Do not need to remove eyeglasses The Center hold method is much faster but is also less precise.
ORIENTING THE MAP A MAP IS ORIENTED WHEN IT IS IN A HORIZONTAL POSITION WITH ITS NORTH/SOUTH CORESPONDING TO THE NORTH/ SOUTH ON THE GROUND 1. look for the 5 major terrain features 2. Compare the vegetation depicted on the map 3. Use the inland bodies of water 4. Use man made features 5.use anything on the map that will assist you in navigation This is the preferred method for orienteering
COMMONLY USED PROTRACTOR MILITARY PROTRACTOR BASE LINE DEGREES Baseline 2 scales DEGREES which coorespond to the 360 deg of a compass and Mils 6400 1 degree = 17.7 mil MILS THE GTA 5-2-12 IS THE MOST COMMONLY USED PROTRACTOR FOR MAP READING. FM 21-26: PAGE 6-4 & 6-5 (FIGURE 6-6 & 6-7) INDEX
GRID COORDINATES To locate any coordinate: Must go RIGHT then UP Four Digit Coordinate Location Within 1000m (RP5904)
Eight Digit Coordinates GRID PRECISION Six Digit Coordinates Locate a point within 100 meters Eight Digit Coordinates Locate a point within 10 meters
RP59850432
VGT 5
VGT 7
TERRAIN IDENTIFICATION TEST Stations: Shoot two azimuths, either in MILS or DEGS using both methods. a) Given a known point ID its 4-Digit or 8-Digit coordinate. 3) a) Find Pace Count. b) Given a 4 digit and an 8 digit coordinate plot both points and ID the Feature or structure.
TERRAIN FEATURES Five Major Three Minor Two Supplementary Hilltop, Valley, Ridge, Saddle, Depression Draw, Spur, Cliff Cut, Fill