R: Draw and export circle maps to PDF

snippets.R

## Export circle map to PDF
pdf("US04Election-PopBin.pdf")
 
  # Draw the USA outline
  map('usa', fill=T, col="white", bg="darkgray")
  # Create the colors for the states
  col <- rep(rgb(.1,.1,.1,.2), length(counties$names))
  col[election$order] <- bluered(election$Bush,election$Kerry, .4, graded=F)
  # Plot states without borders (should work with map, see help for fill
  # argument, but cannot get it working)
  m <- map('county', fill=T, plot=F)
  polygon(m$x, m$y, col=col, border=NA)
  # Draw county borders
  map('county', col="darkgrey", add=T)
  # Draw state borders
  map('state', col="black", add=T, lwd=2)
  # Color for circles
  col <- bluered(election$Bush, election$Kerry, .6)
  # Symbols is the easiest way to draw circles that have the right aspect ratio
  symbols(election$x, election$y, circles=log(election$sizeR+1)*3,fg=col, bg=col, add=T, inches=F)
 
dev.off()