정오표

324쪽 둘째 줄 http://maps.worldbank.org/overlays/2712 -> http://jaredlander.com/data/worldmap.zip

324쪽 여덟째 줄 코드
> download.file(url=”http://maps.worldbank.org/overlays/2712.zip”, destfile=”data/worldmap.zip”, method=”curl”) 을 다음으로 교체
> download.file(url=”http://jaredlander.com/data/worldmap.zip”, destfile=”data/worldmap.zip”, method=”curl”)