Unit%20I%20-%20Maps

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Unit I - Maps
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Cartography

• Cartography science of map-making
• Cartographers must choose
• Types of projections
• Levels of simplification
• Levels of aggregation
• Map scale
• Symbols to use

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Maps

• All maps are created by projecting the earths 3D
  shape, which in reality is a bumpy oblate
  spheroid or geoid, onto a 2D surface.
• 3D shapes can never truly be 2D
• All flat maps have some distortion in their
  representation of distance, shape, area, or
  direction.

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Map Projections

• There are many possible map projections.
• A cartographer must choose the one which will
  best represent their purpose for the map.
• No best projection the one chosen depends on
  the data they wish to represent.

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Mercator Projection

• Preserves compass direction, distorts the area of
  landmasses relative to each other (higher
  latitudes larger in size)

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Fuller Projection

• Maintains the accurate size and shape of
  landmasses but completely rearranges direction,
  so that the cardinal directions no longer have
  any meaning

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Robinson Projection

• Provides an aesthetically pleasing balance (does
  not maintain accurate area, shape, distance, or
  directionbut minimizes errors)

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Azimuthal Projection

• Either the North or South pole is at the center
  of the map

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Level of Simplification

• Refers to the level of detail included
• What cartographers choose to display on the map
  depends on the overall purpose of the map and the
  size of the area covered

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Level of Aggregation

• Refers to the size of the unit under
  investigation such as cities, counties, states,
  or countries
• Depends on the purpose of the map

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Scale

• Refers to ratio between the distance on a map and
  the actual distance on the earths surface
• Small-scale the ratio between map units and
  ground units is small (usually for large areas)
• Large-scale cover much smaller regions

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Resolution

• Refers to a maps smallest discernable unit
  smallest thing you see on a map.

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Map Categories

• 2 categories
• Reference maps work well for locating and
  navigating between places.
• Thematic maps display one or more variables
  across a specific space.

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Symbols

• Isoline (contour) lines that represent
  quantities of equal value and are familiar to
  those who use topographic maps for navigation
  also used to represent values (population
  density).
• Proportional symbols the size of the chosen
  symbol such as a circle or triangle indicates
  the relative magnitude of some value for a given
  geographic region.

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Type of Maps

• Location charts convey a large amount of
  information by associating charts with specific
  mapped locations.
• Dot maps use points to show the precise
  locations of specific observations or occurrences
  (crime, births).

Example of Dot Map
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Type of Maps Cont.
Example of Choropleth Map

• Choropleth maps use colors or tonal to
  represent categories of data for given geographic
  areas.
• Cartograms transform space, such that the
  political unit a state, country, with the
  greatest value of some type of data is
  represented by the largest relative area.

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Visualizations

• Another interesting class of maps become
  increasingly popular in recent years.
• Use sophisticated software to create dynamic
  computer maps, some of which are 3-D or
  interactive.

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Cognitive Mental Maps

• An individuals internal, geographic
  understanding of a place.
• Formed when people perceive information about
  their surroundings and then process that
  information into a mental image that reflects
  both the physical environment and that
  individuals social, cultural, and psychological
  framework.
• May include hazards items/places a person
  avoids during their daily routine.

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Preference Maps

• Show peoples ideas about the environmental,
  social, or economic quality of life in various
  places.

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Location/DistanceGeographers use these to
establish location and distance

• Coordinate system
• Absolute location
• Longitude and latitude
• Meridians Prime Meridian
• International Date Line

• Parallels
• Site
• Situation Relative location
• Absolute distance
• Relative distance
• Connectivity
• Time-Space Convergence