Map

1
Map Compass

• Developed from
• The Essential Wilderness Navigator
• By David Seidman Paul Cleveland

2
Types of Maps
Planimetric Road Map
National Ocean Survey Chart
USGS Topographic Map
Cape Rosier, Maine
3
USGS Topographical Maps

• Symbols
• Legend
• Contour Lines
• Slope Profiles
• Slope Gradient
• Latitude Longitude
• Scale
• Declination

4
Perspectives
A rugged landscape as depicted
X
(1) on a topo map
(2) from a birds-eye view
(3) Your view south from the spot marked X
5
Shaded Relief
USGS Topographical
Same Quad with Shading
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Reading the Terrain
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Contour Lines
Gentle Slope
Ridge or Summit
Mountainside w Cliff
Moderate Slope
Bowl
Gully
Steep Hill
Saddle, Pass, or Col
Ridge
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Rules for Interpreting Contours

• There is no beginning or end to a contour line.
  It is an irregularly shaped closed loop.
• The steeper the slope, the closer the spacing
  between lines.
• Your trail is going uphill if it regularly
  crosses contour lines of increasing elevation.

• Valleys usually show up as a series of V-shaped
  lines pointing toward higher ground.
• Ridges can be shaped like a series of Vs or Us
  pointing toward lower ground.
• A pass or saddle in a ridge has higher contour
  lines on each side, giving it a characteristic
  hourglass shape.

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Rules for Interpreting Contours

• To determine if a group of U or V shaped contours
  shows a ridge or a valley, check the elevation of
  the contour indexes to see which way the ground
  is sloping, or check to see if a stream runs down
  the middle or side of the Vs.

• Contour lines running up one side of a river or
  stream, crossing it, and running back down the
  other side form a U or a V that points upstream.
• A peak is depicted by the innermost ring of a
  near-concentric pattern of contour lines. It is
  marked with elevation and sometimes an X.

10
Scale

• A map is reality reduced to manageable size, with
  every detail uniformly proportioned to what it
  represents. The maps scale, or degree of
  reduction, is noted along its bottom border.
• Scale is most often expressed as a ratio called
  representation fraction.

• A scale of 124,000 means that 1 inch on the map
  represents 24,000 inches in the real world.
• The bigger the second number, the smaller the
  scale the smaller the second number, the larger
  the scale.

1250,000 small scale small detail 124,000
large scale large detail
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Slope Gradient

• We utilize slope gradient as an important
  variable in determining a trails level of
  difficulty.
• The change in elevation, which is the vertical
  distance (contour lines)
• The length of the trail, which is the horizontal
  distance (maps scale)

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Route Profile
13
Slope Perspective

• Four views of a mountain.
• A familiar landmark can look very different when
  viewed from an unfamiliar perspective.

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Latitude Longitude

• Lines of latitude run horizontally, East West,
  and lie parallel to one another.
• Measure distance North South of the equator.
• Lines of longitude run vertically North South,
  but are not parallel.
• Measure distance East West of Greenwich,
  England.

15
Which Way is North?

• Geographic or True North
• At one end of the axis around which the earth
  spins.
• Map makers place geographic North at the top of
  the world.
• Magnetic North
• At the Northern end of the planets magnetic core,
  West of Baffin Island.
• The compass is attracted to magnetic North.

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Declination The Difference between Geographic
and Magnetic North
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Direction
Cardinal Intercardinal points
Degrees
Typical combination
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Compass Types
Fixed Dial
Magnetic Card Marine Car
Magnetic Card Military Lensatic
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Baseplate Compass
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When All Else Fails

• Iron or Steel
• A pin or Needle
• Piece of Barbed Wire
• No Drafts
• Small Container
• Magnetize if Possible
• Magnet
• Stone
• Silk

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Map Software

• TopoUSA

22
Skills Challenge

• topoliteracy

23
Challenge

• Test your topoliteracy by matching the topo views
  on the left (1 5) to the appropriate profiles
  on the right (A E).