Maps

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Maps
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• Do you know what a map of the world looks like?
• Are you sure?
• How sure?
• Describe it

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Map Grid

• Latitude /Longitude
• Tropics
• Equator
• Prime Meridian /International Date Line

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Gain a Day
Skip a Day
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• Immediately to the left of the International Date
  Line, the date is always one day ahead of the
  date immediately to the right of the
  International Date Line. On the time and date
  codes shown below, note that Tonga and Samoa have
  the exact same time, but are actually one day
  apart, as Samoa is in the Western Hemisphere (to
  the east of the dateline) and Tonga is in the
  Eastern Hemisphere. In summary, travel west
  across the International Date Line and you will
  gain a day, travel east across it and you will
  lose a day.

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All Maps should Have

• Cartographer
• Title
• Scale
• Key

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Map projection is the way we fit earths
three-dimensional surface onto flat paper or a
screen
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• On a map, when lines of latitude and longitude
  cross what is the resulting angle?

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Pencils Down The following information is for
background knowledge only.
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Map Projections

• Think of an transparent globe
• w/ an imagined light source inside

• What type of shadow would be cast?

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Shadow cast would depend on light location

• Gnomonic light source at center
• Stereographic light at point opposite of
  tangent of globe meeting map
• Orthographic light source at infinity

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Onto What do you project

• An azimuth is the angle formed at the beginning
  point of a straight line, in relation to the
  meridian

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Position of the surface
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The Math
Just Kidding

• Derivation of the Projection
• cosfdR?dRcosf
• cos?p2d?p2dcos?Rcosfcos?
• sin?p1d?p1dsin?Rcosfsin?
• Derivation of the Inverse
• d?p?
• cos?p2?p???cos-1(p2?p?)
• cosfdR?fcos-1(?p?R)

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• The Most Common
• Conformal (i.e., angles are preserved)
• Equal Area (i.e., areas are in constant
  proportion)
• Equidistant (i.e., distances are in constant
  proportion)
• An Important Mathematical Result
• A single projection can not be both conformal and
  equal area

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Polar Azimuthal Orthographic
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Sinusodial Projection
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Equatorial Cylindrical Equal Area
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Equatorial Cylindrical Conformal
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Conical Equal Area
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Three sources of map distortion

• Map scale most maps are smaller than the
  reality they represent. Map scales tell us how
  much smaller.
• Map projection this occurs because you must
  transform the curved surface of the earth on a
  flat plane.
• Map type you can display the same information
  on different types of maps.

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Mercator Projection
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Equal Area Projection
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Robinson Projection
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Goodes Projection
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Peters Projection
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• The Peters Projection World Map is one of the
  most stimulating, and controversial, images of
  the world. When this map was first introduced by
  historian and cartographer Dr. Arno Peters at a
  Press Conference in Germany in 1974 it generated
  a firestorm of debate. The first English-version
  of the map was published in 1983, and it
  continues to have passionate fans as well as
  staunch detractors.The earth is round. The
  challenge of any world map is to represent a
  round earth on a flat surface. There are
  literally thousands of map projections. Each has
  certain strengths and corresponding weaknesses.
  Choosing among them is an exercise in values
  clarification you have to decide what's
  important to you. That is generally determined by
  the way you intend to use the map. The Peters
  Projection is an area accurate map.
• http//www.petersmap.com/page2.html