United States Coastline and State Boundaries

DESCRIPTION:

Puts all or part of the United States on the current or a new plot, with or without state boundaries.

USAGE:

usa(states=T, coast=T, add=F, xlim=c(65,135), ylim=c(24,50), fifty=F)

OPTIONAL ARGUMENTS:

states

logical flag to control whether state boundaries are plotted.

coast

logical flag to control whether the coast-line is plotted.

add

logical flag: if TRUE, the plot is superimposed on the existing plot; otherwise, a new plot is generated.

xlim

limits for the x-axis (longitude).

ylim

limits for the y-axis (latitude).

fifty

logical flag: if 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 par ).

SIDE EFFECTS:

a plot is produced on the current graphics device. It is added to the current plot if add=TRUE, and creates a new plot otherwise.

DETAILS:

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 map of the U.S.

EXAMPLES:

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)