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Project 5 Thematic Maps

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Project 5 Thematic Maps Powered By Docstoc
					    Project 5
  Thematic Maps
Aaron Henning & Carl Sherlock
        Thematic Maps Basics
► Transfer  geographic data into geographic
  information
► Highlight one attribute’s geographic
  distribution
► Single purpose or “theme” in mind
► Review: Reference maps portray many
  attributes and features
Reference vs. Thematic
             Thematic Maps
►  Use abstract, graphic symbols that
  represent the quantities and qualities that
  make locations meaningful
► The use of colors and symbols to project
  attribute data
► Attribute data examples: density, counts,
  rates, etc.
► Cynthia Brewer’s presentation
Remember…
            Thematic Mapping
► Counts
   Showing a symbol for
    each individual or group
    of individuals
   Fails when many
    individuals or groups
    are present and/or
    when location is
    unknown
             Thematic Mapping
► Porportional   Symbol
  Maps
   Also called graduated
    symbol maps
   They represent classes
    of counts not individual
    counts
   Useful for counts that
    lack location
            Thematic Mapping
► Chloropleth   – “place” &
  “value”
   Involves coloring
    geographic areas to
    represent categories of
    rates or densities
   Most common type of
    thematic map
             Thematic Mapping
                                Pie Chart

► Rates   and densities
   Simply one count
    divided by another
    count
   In densities, the divisor
    is the magnitude of a
    geographic area             Bar Graph

   Can be in various
    formats
          Starting the Project
► Go  to
  factfinder.census.gov
► Left side menu, hover
  cursor over “DATA
  SETS”
► Click on “Decennial
  Census”
►   Making sure you are selecting
    “Census 2000 Summary File
    1”, choose “Thematic Maps”
    on right hand menu




►   Select “county” under
    geographic type
►   Select your state, then select
    your county, and hit “Next”
►   This will display all of the
    data themes that can be
    displayed on a map  pick
    one and click “Show Result”
►   Directly above map
    where it says
    “Display map by:”,
    select “Census
    Tract” from drop-
    down menu



►   Adjust zoom and
    pan to make data as
    visible as possible
► At top of left
  side menu under
  “Change…”,
  select “data
  classes”
► From here you
  can change
  classing method,
  color scheme,
  and number of
  classes
         Classing Methods Review
►   Quantile (percentile)
     Equal number of features in each class
►   Equal Interval
     Equal range of values in each class
►   Natural Breaks
     Divides features and/or range of values according to pre-existing
      groupings or divisions
► When  finished
 customizing, right
 click map and select
 “Save picture as...”
 (repeat for legend)
► You   have now
  successfully found
  and downloaded
  all data for your
  first map
► For this project,
  you need a total of
  3 maps
     ► At least one needs
       to be of ACS Data
     ► From FactFinder
       homepage, hover
       over “Data Sets”
       and click on
       “American
       Community
       Survey” and follow
       same process
► Takea moment
 to analyze your    Think about this, it will help you with the write-up
 map – why is the
 data how it is?

                          Map 1: Percent Persons Under 18 Years of Age
► Why  does the
 tract that
 corresponds to
 campus and
 downtown have
 the lowest
 percent of
 persons under
 18?
             Finding Map Scale
► In bottom left corner
  of your map image, it
  will tell you distance
  across (Dg)
► The actual width of the
  image is ~6” (Dm)

► Remember   the
  formula?
  S = D m / Dg
                  Review
► Thematic   Mapping
► Attribute data transformed into useful
  geographic information
► Designed with a central purpose or theme
► Different types of data are represented in
  different ways
                           References
►   Baxter, Ryan. Census Mapping and Thematic Maps. GEOG 121 Lecture.
    11/20/06
►   Brewer, Cynthia. Cartographic Inspirations for Designing Better Data
    Visualizations. GEOG 121 Guest Presentation. 10/11/06
►   Census Bureau FactFinder. Accessed 11/20/06. http://factfinder.census.gov
►   ESRI Virtual Campus: Module 6. Accessed 11/19/06. http://training.esri.com
►   The Pennsylvanian Marketing and Planning Center. Accessed 11/20/06.
    http://www.mapcenter.org/index.html
                              Help
► Aaron  Henning – amh334@psu.edu
► Carl Sherlock – cfs5000@psu.edu
   http://personal.psu.edu/cfs5000/geog121_lab5.html

► Course     Example
   http://www.geog.psu.edu/courses/geog121/projects/proj5_example.html

				
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