[R graphics] Map

There are many things R can do, GIS maping is one of it. If you have the ESRI shape file ready, use maptools package to read the shape file into R. The R code is as follows.

# R code
library(maptools)
tw.map <- read.shape("taiwan.shp")
res <- plot(tw.map, auxvar=tw.map$att.data$POP06,
color="red", axes=F, xlab="", ylab="", pty="m")
str(res)
n.shp <- length(tw.map$Shapes)
x.pts <- tw.map$att.data$XLAB
y.pts <- tw.map$att.data$YLAB
legend(locator(1), legend=leglabs(round(res$breaks/10000,0)),
fill=res$ramp, bty="o", cex= 1.2, pt.lwd=3, title="人口(萬人)")
text(x=x.pts, y=y.pts, labels=tw.map$att.data$CNAME, cex=0.7)
rect(955, 1600, 1015, 1660, lty=2)
rect(1010, 1682, 1070, 1742, lty=2, xpd=T)
#rect(locator(1)$x,locator(1)$y,locator(1)$x,locator(1)$y)