Visualizing Spatial Relationships - Data Points: Visualization That Means Something - page 283

FIGurE 8-8 Drawing worldwide connections
After you create the base map, you can loop through each point and draw a
line from the last point in the data frame to every other location. This isn't
incredibly informative, but maybe you can find a good use for it. The point
here is that you can draw a map and then use R's other graphics functions
to draw whatever you want using latitude and longitude coordinates.
By the way, I wasn't actually a spy for Fakesville. I was just kidding
about that.
Scaled Points
Switching gears back to real data and a more interesting topic than my
fake spy escapades, more often than not, you don't just have locations. You
also have another value attached to locations such as sales for a business
or city population. You can still map with points, but you can take the prin-
ciples of the bubble plot and use it on a map.
I don't have to explain how bubbles should be sized by area and not radius
again, right? Okay, cool.
MAP WITh bubbLES
In this example, look at adolescent fertility rate as reported by the
United Nations Human Development Report—that is, the number of
births per 1,000 women aged 15 to 19 in 2008. The geo-coordinates were