Land Navigation I

10/30/20153 Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth, and North ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/20154 Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth, and North ► ► Questions? ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth

10/30/20155 Map Basics ► ► Definition: A map is a mathematically determined representation of the Earth’s surface systematically plotted to scale upon a plane surface.

10/30/20156 Map Basics: ► ► Information that helps us read & interpret a map   Graphic (bar) scales are rulers used to convert horizontal map distance to ground distance ► ► Right of 0 is primary scale ► ► Left of 0 is extension scale Marginal Information

10/30/20157 Map Basics: Marginal Information (cont.) METERS 1000 PRIMARY SCALE EXTENSION SCALE

10/30/20158 Map Basics: ► ► Declination Diagram   True North   Grid North   Magnetic North Marginal Information (cont.)

10/30/20159 Map Basics: Declination Diagram MAGNETIC NORTH TRUE NORTH GRID NORTH Note: See Declination Diagram on Handout Map

10/30/ Map Basics: ► ► Legend  Illustrates and identifies the topographic symbols used to depict prominent features on the map. Symbols on one map may not mean the same things on another map Marginal Information (cont.)

10/30/ Map Basics: Legend Note: See Legend on back of Handout Map Includes all kinds of information, from the size/condition of roads to mines, chapels and other man-made features.

10/30/ Map Basics: ► ► Map Scales  Representative Fraction is the scale of the map which expresses the ratio of horizontal distance on the map to the corresponding horizontal distance on the ground: ► 1:25,000 SCALE. ► 1:50,000 SCALE ► 1:100,000 SCALE ► 1:250,000 SCALE  The smaller the number on the bottom, the larger the scale of the map Marginal Information (cont.)

10/30/ Map Basics: ► Small scale maps - Maps that have a scale of 1:1,000,000 and smaller. These maps are used for general planning and for strategically studies at the higher echelons. ► The standard small scale map is 1:1,000,000 Map Scales (cont.)

10/30/ Map Basics: ► Medium scale maps - Are maps of scales that are larger than 1:1,000,000 but smaller than 1:75,000. ► These maps are used for planning operations, including the movement and concentration of marines and supplies. ► The standard medium scale map is 1:250,000. Map Scales (cont.)

10/30/ Map Basics: ► Large scale maps - Are maps that are 1:75,000 and larger. ► They are used to meet tactical, technical, and administrative needs of the field units. ► The standard Large scale map is 1:50,000. Map Scales (cont.)

10/30/ Map Basics: Colors ► Black: Man-made objects  Buildings, some roads, cultural, etc. ► Red: Main roads  Also some special features ► Blue: Water features  Lakes, rivers, ponds, ocean, etc. ► Green: Vegetation  Forrest, orchard, etc. ► Brown: Relief features  Contour lines.

10/30/ Map Basics: Grid Lines ► A series of straight lines intersecting at right angles forming squares ► Horizontal grid lines run grid west to grid east ► Vertical grid lines run grid south to grid north ► On most military maps a grid square is 1000X1000 meters ► Basic Rule: Read right on the vertical lines, then up on the horizontal grid lines

10/30/ Map Basics: Grid Lines m E m N

10/30/ Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth Conversion, and Norths ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/ Digit Grid Coordinate ► A grid square’s coordinates are found by combining the values of the vertical and horizontal grid lines that intersect at the lower left hand corner of the grid.  Always, read right, then up  A 4-digit grid coordinate locates a point to within 1000 square meters.

10/30/ Finding a 4-Digit Grid Coordinate m E m N GRID REFERENCE: 4820

10/30/ Coordinate Scale ► Divides the grid square more accurately and consistently that estimation  1:25000 coordinate scale divides the 1000 square meter block into ten 100 meter divisions, the ten divisions are further divided into 20 meter blocks

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10/30/ Finding the Grid Coordinate of a Point ► First determine the grid square the point is in. This gives 4 digits: 12xx56xx. ► Next, using correct scale on protractor, align the bottom right corner of the protractor scale to the bottom right corner of the grid square.  Slide the protractor to the left until the right edge of the scale intersects the point.  Read off the horizontal and vertical position: ►

10/30/ Grid: Gives second two longitude (horizontal) coordinates: 85 Gives second two latitude (vertical) coordinates: 55

10/30/ Plotting a Grid Coordinate ► Grid Coordinate  Divide into horizontal and vertical measurements:  Next locate primary coordinates that give grid square: ► : 12 and 56 are primary coordinates that provide the grid square ► The 34 and 78 and determined by using the tick marks on the protractor

10/30/ Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth Conversion, and Norths ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/ Determining Distance: Straight Line  The shortest distance between the two points  Lay a straight piece of paper between two points  Make two tickmarks on the paper corresponding to the centers of the two points  Move the paper down to the graphic scale  Make sure you use meters

10/30/ Determining Distance: Irregular Line ► Used for winding roads, curved lines  Lay paper down so one edge is on the start point, make a tick mark at the start point and another where the edge of the paper leaves the center of the curve/line  Pivot the paper with the pencil on the second point ► to align the paper with the center of the curve, make another tick mark when the paper leaves the center of the curve  Continue until measurement is completed  Transfer paper to the graphic scale to compute the distance

10/30/ Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth Conversion, and Norths ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/ Contour Lines: Basics  A contour line is a line drawn on a map representing an imaginary line on the ground along which all points are the same elevation  Indicates the vertical distance above or below a base plane  The vertical distance between two lines is the contour interval, found in the marginal data  Every fifth line is an index contour, it is shaded thicker and heavier  The lines in between are intermediate contours  Every line counted represents a change in elevation equal to the contour interval

10/30/ Contour Lines: Basics x Index Contour LineIntermediate Contour Line Supplementary Contour Line

10/30/ Contour Lines: Determining Elevation ► If a point is on a line its elevation is that of the contour line ► For the estimation of elevation of a point between contour intervals is equal to 1/2 change in contour interval  A hilltop is 1/2 plus the elevation of the contour line around the hilltop unless otherwise stated  A depression is equal to the contour line around the depression minus 1/2 the contour interval

10/30/ Contour Lines: Elevation x Elevation of Point: 7 = ? 3 = ? 9 = ? 1 = ? 4 = ? 8 = ? 10 = ?

10/30/ Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth Conversion, and Norths ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/ Relief & Terrain Features: Slopes ► Evenly spaced and wide apart contour lines indicate a uniform gentle slope ► Evenly spaced and close together contour lines indicate a uniform steep slope ► Lines closely spaced at the top and widely spaced at the bottom is a concave slope ► Lines widely spaced at the top and closely spaced at the bottom indicates a convex slope

10/30/ Relief & Terrain Features: Slopes Uniform Gentle Slope Uniform Steep Slope Convex SlopeConcave Slope

10/30/ Relief & Terrain Features: Terrain Features ► Hill: Indicated by closed loop. The ground slopes down in all directions ► Draws: Less developed stream courses  ground slopes upward in three sides and down one side.  V points to higher elevation

10/30/ Relief & Terrain Features: Terrain Features ► Ridge: A line of high ground with normally minor variations along its crest  Not simply a line of hills  The points of the ridge are higher than the ground around it ► Finger: A continous line of sloping ground usually jutting from the side of a ridge

10/30/ Relief & Terrain Features: Terrain Features ► Saddle: A dip or low point along the crest of the ridge ► Cliff: A vertical or near vertical slope. So steep it is indicated by tick-marks pointing to lower elevation

10/30/ Relief & Terrain Features: Terrain Features ► Depression: A low-point or sinkhole surrounded on all sides by higher ground  Tick marks point to lower ground  Each ticked contour circles represents a change in elevation equal to one contour interval ► Valley: A stretched-out groove in the land  Usually formed by streams or rivers

10/30/ Relief & Terrain Features: Terrain Features ► Cuts: places where high ground leveled off ► Fills: areas where low areas are filled in

10/30/ Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth Conversion, and Norths ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/ GM Angle, Azimuth Conversion, and North ► Three Norths  Grid-The vertical lines on the map  Magnetic-Magnetic North in Hudson Bay  True-North Pole ► Declination Diagram shows the relationships between the three norths ► Magnetic and Grid North are used to determine GM (Grid-Magnetic) Angle

10/30/ Azimuths ► An azimuth is a direction ► Defined as a horizontal angle measured clockwise from a baseline ► There are two types dealt with  magnetic azimuths measured with true north as its base  grid azimuths measures with grid north as base

10/30/ Measuring Azimuths ► Plot two coordinates on the map ► connect them with a straight line ► Place the index point pf the protractor on the point the azimuth its to be measured from ► Ensure the protractor grid lines are parallel to N-S gridlines on a map ► Where the line crosses the protactor indicates azimuth

10/30/ Azimuths (cont.) m E m N GN Grid azimuth = 45 degrees

10/30/ Converting Azimuths ► Use the GM angle to convert grid to magnetic and magnetic to grid ► When going from Grid to Magnetic  LARS ( Left Add/ Right Subtract)  This will almost always be the case ► Magnetic to Grid  LSRA (Left Subtract/Right Add)

Questions?

10/30/ Presentation Overview ► ► Map Basics   Definition   Marginal Information   Map Colors   Grid Lines ► ► 8-Digit Grid Coordinate   Locating   Plotting ► ► Determining Distance   Straight-Line Distance   Irregular Distance ► ► Contour Lines   Basics   Determining Elevation ► ► Relief & Terrain Features   Slope Types   Hill, Draw, Ridge, Finger, Saddle, Cliff, Depression, Cuts, Fills ► ► GM Angle, Azimuth Conversion, and Norths ► ► Quiz ► ► Next Time: Land Navigation II   Lensatic Compass   Orienting a Map   Determine an Azimuth   Follow an Azimuth ► ► Questions?

10/30/ Quiz ► What is a map? ► What are the three types of North?  Explain what they represent. ► What standard colors are used on a map?  What do they represent? ► Explain the 2 main types of contour lines. ► What is an 8-digit grid coordinate?  How accurate is it is using a 1:25000 coordinate scale? ► Describe the four types of slope and what they look like on a topographic map.

10/30/ Quiz (cont.) ► What is the following terrain feature: ► Is this the GM angle for San Francisco or New York? Why?  If I am going from Grid to Magnetic on a map with this angle, would I add or subtract this angle?

10/30/ Next Time: Land Navigation II   Lensatic Compass ► ► Parts ► ► Using during day ► ► Using at night   Orienting a Map   Determine an Azimuth   Follow an Azimuth   Pace Count