Maps

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Maps
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• Who demonstrated the Earth was round using maps?
• a. Ptolemy b. Aristotle
• c. Eratosthenes d. Sauer
• Who coined the word geography?
• a. Ptolemy b. Aristotle
• c. Eratosthenes d. Sauer

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Evolution of Mapmaking

• Babylonians 2300 BC earliest surviving maps
  written on clay tablets.
• Aristotle 384-322 BC demonstrated earth was
  spherical through maps.
• Eratosthenes 276-194 BC first person to use the
  word geography. Also the first person to
  correctly divide earth into 5 climatic regions.
• Ptolemy 100-170 AD Guide to Geography
• Age of Exploration by the 17th century, most
  continents and oceans were accurately displayed.

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Contemporary Mapping

• GIS (geographic information systems)
• GPS (global positioning system)
• Remote Sensing Satellites

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• a. Remote Sensing b. GPS
• c. GIS d. DTM
• Layers of geographical information that can be
  selected or deselected when viewing a map
• Can immediately scan the Earths surface to
  determine changes in geography

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GIS Layers
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Use of GIS in Emergencies
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Remote Sensing

• The acquisition of data about Earths surface
  remotely such as from an airplane or satellite
  orbiting the planet.
• Primarily environmental mapping vegetation,
  surface cover, winter ice cover, deforestation

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Satellite images of the north-east coast of Japan
before (left) and after the earthquake and
tsunami. Water is black or dark blue and the thin
green line in the 'after' image indicates the
shoreline. Photograph Nasa

• http//www.nytimes.com/interactive/2011/03/13/worl
  d/asia/satellite-photos-japan-before-and-after-tsu
  nami.html?_r0
• http//eijournal.com/2011/disaster-response-in-jap
  an-2

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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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How to Lie with maps

• A map is a generalization or representation of
  the real world.
• Cartography the science of mapmaking.
• All maps lie flat and all maps lie. They contain
  distortions. You cannot represent the
  three-dimensional earth on a flat surface without
  distorting reality.
• Any useful map is selective in what is put in and
  left out. Example road or subway map.

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Is this a correct map of London?
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Is this a correct map of London?
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Which map would be useful to tour London?
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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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Map Type you can display the same information
on different maps

• Types of maps
• Dot each dot represents some frequency
• Isoline connects points of equal value
• Choropleth puts features into classes and then
  maps classes for each region
• Cartogram adjusts the size of the country
  corresponds to the magnitude of the mapped
  feature
• Proportional symbol size of the symbol
  corresponds to the magnitude of the mapped
  feature

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Dot each dot represents some frequency
Chart Map
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Isoline connects points of equal value
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Choropleth puts features into classes and then
maps classes for each region
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Proportional symbol size of the symbol
corresponds to the magnitude of the mapped
feature
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Cartogram adjusts the size of the country
corresponds to the magnitude of the mapped
feature
http//www.worldmapper.org/
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Other Thematic Maps- spatial distribution of one
or more specific themes
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What kind of map is this?
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What kind of map is this?
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What kind of map is this?
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What kind of map is this?
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Other types of visual images

• Mental map map of an area in your mind

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B
A
D
C
Proportional Symbol?
E
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B
A
D
C
Dot Map?
E
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B
A
D
C
Isoline?
E
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B
A
D
C
Cartogram?
E
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B
A
D
C
Choropleth?
E
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B
A
D
C
Good for showing points of equal value?
E
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How can such different looking maps show the same
variable?

• Cartographic reasons
• Different slicing values
• Different levels of spatial aggregation
• Geographical reasons
• Uneven distribution of minorities at the state
  scale as well as at the national scale
• Concentration of minorities in cities,
  particularly in northern states

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Different ways of slicing data

• The Data 42, 50, 55, 57, 61, 77, 79, 97
• Equal interval
• Three classes based on range 40 to 100
• 42, 50, 55, 57 61, 77, 79 97
• Quantile
• Quartiles (lowest 1/4 of observations, next 1/4,
  )
• 42, 50 55, 57 61, 77 79, 97

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Different ways of slicing data

• Natural breaks
• 428505552574616772791897
• 42 50, 55, 57, 61 77, 79 97
• Standard deviations
• Mean 64.75, Std. Dev. 15.977
• 42 50, 55, 57, 61 77, 79 97

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Natural Breaks
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Equal Interval
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Quintiles (quantiles based on division into 5
classes)
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Which map would be preferred by each of the
following users?

• The ACLU
• The KKK
• A geographer studying the relationship between
  ethnicity and poverty
• A spokesman for the Georgia branch of a
  charitable assistance association targeting
  minorities