usa(states=T, coast=T, add=F, xlim=c(-130,-65), ylim=c(24,50), fifty=F)
TRUE
, the plot is superimposed on the existing
plot; otherwise, a new plot is generated.
TRUE
, boxes are drawn in the Pacific Ocean to
represent Alaska and Hawaii.
Graphical parameters may also be supplied as arguments to this function (see ).
add=TRUE
,
and creates a new plot otherwise.
The plot is done in correct physical proportion. The coordinate system set up for the plot uses negative longitude, so that x-values increase from left to right on the plot.
The
maps
library contains a more detailed
and accurate map of the United States down to the county level
and is recommended over the
usa
function.
usa(states=F) # the U.S. without state lines usa(xlim=c(65, 85), ylim=c(35, 50)) # plot the north-east usa() text(state.center, state.abb, cex=.5) # Plot and label a handful of zip codes # on a usa() map using latitude and longitude values dxdy <- data.frame( P.O. = c("Oostburg", "Santa Paula", "Ukiah", "Edmonds"), State = c("WI","CA","CA","WA"), ZipCode = c(53070, 93060, 95482, 98020), Latitude = c(43.6252, 34.3776, 39.1539, 47.8000), Longitude = c(-87.7984, -119.1058, -123.2580, -122.3719), stringsAsFactors = F) usa() points(x = dxdy$Longitude, y = dxdy$Latitude, pch = 16, cex = 0.4, col = 8) text(x = dxdy$Longitude, y = dxdy$Latitude, labels = dxdy$P.O., cex = 0.4, col = 8, adj = 1)