US.r
"US" <-
function (xlim = c(-124.7, -67.1), ylim = c(25.2, 49.4), add = FALSE,
shift = FALSE, ...)
{
if (!exists("US.dat"))
data(US.dat)
if (shift) {
ind1<- !is.na(US.dat$x)
ind2<- US.dat$x < 0
US.dat$x[ind2&ind1] <- US.dat$x[ind2&ind1] + 360
xlim<- c(-124.7, -67.1) + 360
}
if (!add) {
plot(US.dat$x, US.dat$y, ylim = ylim, xlim = xlim, xlab = "",
ylab = "", type = "n", xaxt = "n", yaxt = "n", ...)
}
lines(US.dat$x, US.dat$y, err = -1, ...)
invisible()
}