Assignment 10
Cartograms and Unclassed
Maps
Maps of New York State
The maps of New York State seen in this assignment include unclassed maps
and a cartogram, created with the program MAPresso. The first map on the
page is an interactive choroplethic map of the counties of New York, in
which different values, according to U.S. Census Bureau data, are shown
for the variables listed in the dropdown menu.
To produce this map, I created four variable fields in the New York .dbf
file and entered calculations to produce values for population change,
percent Asian, percent Hispanic, and percent under 5 years. I eliminated
most of the fields not shown in this map, and excluded any others I did
not want to display by specifying them in the applet
code. The necessary .jar files were transferred into my web folder, along
with the files created by MAPresso.
Variables seen in the map below include percent population change from
2000-2003, aggregate 2000
and 2003 population figures, and population density for each county. They
also include
both aggregate and derived figures for Asians, Hispanics, and children
under age 5. To see the derived figures for these three variables, select
"Percent Asian," "Percent Hispanic," or "Percent under 5 Yrs." After making
a selection in the menu, move the arrow over any county to
see the corresponding values for that variable.
The next image is a cartogram of New York, showing aggregate 2000
population for each county. Note how much larger the New York City
metropolitan area becomes in proportion to the rest of the state.
I created this image using "print screen," and then cropped it in Lview.
This is only a JPEG image; if you'd like to produce the cartogram
yourself, just click "Geometry" on the program
menu above, and then choose "Start Cartogram." After the program has
resized the image 200 times, you'll see the same view.
Of course, if you wait long enough, the cartogram will keep resizing,
until it stops when the county color fills become identical. You may also
produce a cartogram of the other aggregate variables seen in the dropdown
menu above: Population 2003, Asian, Hispanic, or Under 5 Yrs.
Next you will see a JPEG image of a trivariate map showing values for
percent population change, percent Asian, and percent Hispanic. I clicked
on the legend to display subtractive colors, printed the screen, and
cropped the image in Lview. In a subtractive color scheme, darker colors
indicate higher values, and lighter colors indicate lower values.
Mixed colors (such as purple, a combination of
magenta and cyan) indicate a combination of variables. For example, the
purple coloring in Tompkins County indicates high values for both percent
population change and percent Asians. The dark red color in Kings County
indicates very high values for both percent Hispanic and percent Asian.
The medium yellow color indicates a relatively high value for percent
Hispanic, compared to low values for percent population change and percent
Asian. The light pink color in Herkimer County indicates low
values for all variables, with low-positive
values for percent Asian and percent Hispanic, and a low-negative value
for percent population change.
To produce this map yourself, go to the top
map on the page, click "Colors," then choose "Bi/Trivariate Map." Select
"Pop. change 2000-3," "Percent Asian," and "Percent Hispanic" to duplicate
this map. Or choose another combination of variables for a different
display of values.
Sources:
MAPresso, http://www.mapresso.com
U.S. Census Bureau
Nina Roberts
Spring 2005