Maps, Projections, Tools

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Maps, Projections, Tools

• Unit 1- Introducing Basic Concepts

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Maps

• Geographys most important tool for thinking
  spatially about the distribution of features
  across Earth is a map
• Definition
• A two-dimensional or flat-scale model of Earths
  surface
• Science of mapmaking called cartography

• A map serves two purposes
• Reference tool
• Communications tool

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History of the Map

• Earliest Maps were reference tools
• Designed to show a traveler how to get from Point
  A to Point B
• Important Names
• Eratosthenes
• Coined the word geography
• Determined circumference of the world
• Ptolemy
• Produced maps used for over 1000 years
• Aristotle
• Determined Earth was spherical

• Exploration Age
• Cartography revived during Age of Exploration
  thanks to Columbus, Magellan, and other explorers
• Between 1470-1520 1st map with America labeled
  appears

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Contemporary Mapping

• Uses
• Describe data
• Sources of data
• Tools for analysis
• Example
• Hurricane Katrina
• Representations of the world
• Usually two-dimensional graphic representations
  that use lines and symbols to convey information
  or ideas about spatial relationships

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Types of Maps

• Topographic Maps
• Designed to represent Earths surface and to show
  permanent features such as buildings, highways,
  field boundaries, and political boundaries
• Device for representing the form of Earths
  surface is the contour
• A line that connects points of equal distance
  above or below a zero data point, usually sea
  level

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Types of Maps

• Reference Maps
• Show common features such as boundaries, roads,
  and mountains
• Thematic Maps
• Designed to represent the spatial dimensions of
  particular conditions, processes, or events

• Types of Thematic Maps
• Isopleth maps
• Maps based on isolines
• A line that connects places of equal data value
• Dot maps
• Single dot or other symbol represents a specified
  number of occurrences of some particular
  phenomenon or event
• Choropleth map
• Tonal shadings are graduated to reflect
  variations in numbers, frequencies, or densities

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CHOROPLETH MAP
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• Map Scale
• refers to the relationship of a features size on
  a map to its actual size on earth
• Ratio between linear distance on a map and linear
  distance on Earths surface
• Usually expressed in terms of corresponding
  lengths
• as in one centimeter equals one kilometer
• Or as a representative fraction
• Small scale maps bigger fraction
• Large scale maps smaller fraction

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Scale Differences Maps of Florida
The effects of scale in maps of Florida. (Scales
from 110 million to 110,000)
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Types of Scale

• Graphic
• consists of a bar line marked to show distance on
  the earths surface
• example
• What scale you use depends on what information
  you are portraying

• Fractional
• shows the numerical ratio between distances on
  the map on earths surface
• example 124,000
• Means 1 map unit 24, 000 units on ground
• Written
• relationship between the map and earth distances
  in words
• example 1 inch equals 1 mile
• 1st number represents maps distance
• 2nd number represents earths distance

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Projection
talking map

• Four problems
• the shape of an area can be distorted
• the distance between two points may increase or
  decrease
• the relative size of different areas may be
  altered so that one area may appear larger
• the direction from one place to another can be
  distorted.

• Definition
• the scientific method of transferring locations
  on the earths surface to a flat map
• earths surface is curved and not a perfect
  sphere. It is impossible to represent on a flat
  plane without distortion

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the Solution?????

• Different types of projections
• Equidistant Projections
• can represent distance accurately in only one
  direction (usually north-south)
• usually provide accurate scale in perpendicular
  direction
• most aesthetically pleasing
• Conformal Projections
• Projection on which compass directions are
  rendered accurately

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Types of Map Projections

• Equal-Area
• Relative sizes of the landmasses on the map are
  the same as in reality
• Minimizes distortion
• Mercator
• Shape is distorted little
• Direction is consistent
• Map is rectangular
• Distorts area
• higher latitudes distorted - Greenland appears
  huge!

• Fuller
• maintains accurate size and shape
• completely rearranges direction
• Robinson
• Useful for displaying oceans
• Disadvantage land areas are much smaller
• distorts all 4 but minimizes errors in each (most
  balanced)
• Azimuthal
• puts N or S pole at center of map
• view of looking up or down at earth

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Mercator Projection
The worlds 24 standard time zones are often
depicted using the Mercator projection.
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Different Projections

• Peters
• Deliberate attempt to give prominence to
  underdeveloped countries of equatorial regions
  and the Southern Hemisphere
• Adopted by United Nations
• Shape gives shock value

• Cartogram
• Space is transformed according to statistical
  factors
• Largest mapping units represent greatest
  statistical values

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Geographic Grid

• Definition
• System of imaginary arcs drawn in a grid pattern
  on Earths surface
• The location of any place on Earths surface can
  be described precisely by meridians and parallels

• Meridian
• An arc drawn between the North and South poles
• Location of each meridian longitude
• Measured from the Prime Meridian (0-180 degrees
  East or West)
• Greenwich, England
• Parallel
• A circle drawn around the globe parallel to the
  equator and at right angles to the meridians
• Location of each parallel Latitude
• Measured from the Equator
• (0-90 degrees North or South)

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Basic Tools and Methods of Human Geographers

• Observation
• Information must be collected and data recorded
• Methods
• Fieldwork
• Use of scientific instruments
• Laboratory experiments
• Archival searches
• Remote sensing
• Aerial photography or satellite imagery designed
  to record data on visible, infrared, and
  microwave sensor systems

• Visualization or Representation Written
  descriptions
• Charts
• Diagrams
• Tables
• Analysis
• Heart of geographic research
• Objective analysis is to discover patterns and
  establish relationships so that hypotheses can be
  established and models be built

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Remote Sensing

• Remote Sensing
• acquisition of data about earths surface from
  satellite images that are transmitted in digital
  form.
• Remote-Sensing satellites scan the Earths
  surface
• Geographers use remote sensing to map the
  changing distribution of a wide variety of
  features such as
• Agriculture, drought, and sprawl

• Example
• used with Hurricane Katrina to monitor areas of
  impact

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Global Positioning System (GPS)

• Definition
• System that accurately determines the precise
  location of something on Earth
• GPS in the United States includes three elements
• Satellites placed in predetermined orbits by the
  U.S. military
• 24 in operation, 3 in reserve
• Tracking stations to monitor and control the
  satellites
• A reciever that can locate at least 4 satellites
  to pinpoint locations

• GPS devices enable private individuals to
  contribute to the production of accurate digital
  maps
• Travelers can upload information about streets,
  buildings, etc. to improve maps in the future
• GPS is most commonly used for navigation
• Can also be used for fieldwork for history,
  geography, etc.

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Geographic Information System (GIS)

• Definition
• a computer system that can capture, story, query,
  analyze, and display geographic data.
• Produces maps that are more accurate and
  attractive than hand-drawn maps
• The position of any object on Earth can be
  measured and stored in a computer
• A map can be created by retrieving a number of
  stored objects and combining them to form an
  image
• Each type of information is stored in a layer

• Layers can be compared t0 show relationships
  among different kinds of information

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Layers of a GIS

• Each layer represents a different category of
  information.

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Geographical Information Systems

• GIS technology can render visible many aspects of
  geography there were previously unseen
• Images that could never be drawn by hand
• GIS can put places under the microscope, creating
  detailed new insights using huge databases

• Military applications
• Allows infantry commanders to calculate line of
  sight from tans and defensive emplacements
• Allows cruise missiles to fly below enemy radar
• GIS allows an enormous range of problems to be
  addressed
• Geodemographic research
• Uses census and commercial data about the
  populations of small districts in creating
  profiles for market research