Introduction to Map Reading

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Introduction to Map Reading

• GRC JROTC
• COL(R) ALEXANDER

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Outline

• Purpose
• Marginal Information
• Colors
• Terrain Features
• Conclusion

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Purpose

• To lay the groundwork for successful map reading
  and land navigation by exposing the cadet to
  basic information, significant color coding, and
  terrain features used on maps.

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Marginal Information1 of 4

• Sheet Name
• Sheet Number
• Adjoining Map Sheets Diagram

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Marginal Information2 of 4

• Special Notes
• Declination Diagram

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Marginal Information3 of 4

• Scales
• Contour Interval Notes
• Grid Reference Box

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Marginal Information4 of 4

• Unit Imprint
• Legend

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Colors (x6)

• BLACK Man-made features (Buildings, roads,
  grid-lines)
• RED-BROWN cultural features (contour lines)
• BLUE Water features (Lakes, swamps and rivers)
• BROWN Relief features and elevation on older or
  red-light readable maps (contour lines and
  cultivated land)
• GREEN Vegetation (forest, woods, brush,
  orchards)
• RED Man-made features (populated areas, major
  highway roads, boundaries on older maps)

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Contour Lines Interval

• 1. Check contour interval
• 2. Find given elevation
• 3. Determine direction of slope
• 4. Count contour intervals.

Change in ELEVATION
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Contour Lines Interval
Lines that are farther apart (interval) GENTLE
SLOPE
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Contour Lines Interval
Lines that are close together (interval) STEEP
SLOPE
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Major Terrain Features (x 5)

1. Hill.
2. Valley.
3. Ridge.
4. Saddle.
5. Depression.

H idden V alley R anch S alad D ressing
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Major Terrain Features1 of 5

• Hill An area of high ground
• - Concentric circles. The center of the smallest
  circle is the hilltop.

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Major Terrain Features3 of 5

• Valley a stretched-out groove in the land,
  usually formed by streams or rivers.
• - U or V shaped contour lines. High ground on 3
  sides usually with water flowing in the middle.
  V or U points upstream.

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Major Terrain Features4 of 5

• Ridge This is a sloping line of high ground.
• - low ground in three directions and high ground
  in one direction. Contour lines tend to be
  U-shaped or V-shaped. The closed end of the
  contour line points to lower ground

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Major Terrain Features2 of 5

• Saddle Low point between 2 areas of high ground
• - hour glass or figure eight contour lines.

X
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Major Terrain Features5 of 5

• Depression This is a low point in the ground.
• - Low ground or sink hole. Closed contour lines
  that have tick marks pointing toward low ground.

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Minor Terrain Features (x 3)

1. Draw.
2. Spur.
3. Cliff.

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Minor Terrain Features1 of 3

• Draw a less developed stream course than a
  valley. There is essentially no level ground .
• contour lines depicting a draw are U-shaped or
  V-shaped,
• pointing toward high ground.

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Minor Terrain Features2 of 3

• Spur a short, continuous sloping line of higher
  ground, normally jutting out from the side of a
  ridge.
• - Contour lines depict the U or V pointing away
  from high
• ground.

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Minor Terrain Features3 of 3

• Cliff a vertical or near vertical feature.
• Contour line converge together into one
  Carrying contour. The last contour has tick
  marks pointing towards low ground. Sometimes
  depicted by contours running very close or
  touching.

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Supplementary Terrain Features (x 2)

1. Cut.
2. Fill.

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Supplementary Terrain Features

• Cut or Fill a man-made feature resulting from
  cutting through high ground or filling low
  ground.
• Contour line extends the length of the cut (tick
  marks point to roadbed) and fill (tick marks
  point away from roadbed).

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Practical Exercise
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6
6
1. 2. 3. 4. 5.
6. 7. 8. 9. 10.
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Practical Exercise Key
HILL VALLEY 3. RIDGE 4. SADDLE 5. DEPRESSION
6. DRAW 7. SPUR 8. CLIFF 9. CUT 10. FILL
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Summary

• Purpose
• Marginal Information
• Colors (x6)
• Terrain Features
• Major
• Minor
• Supplementary

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Conclusion

• Knowing how to read and understand maps are
  valuable skills that can strengthen your
  awareness, credibility as a leader, and help you
  standout among your peers.

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Introduction to Map Reading

• GRC JROTC
• COL. ALEXANDER