The following example shows how to get/display the county names: library(maps)
# Get County Data m <- map('county', 'colorado', plot=FALSE) names(m) m$names # State,County names # The names appear to be in alphabetical order by state, e.g.: > m$names[1:3] [1] "colorado,adams" "colorado,alamosa" "colorado,arapahoe" # Show county names on map map.text('county', 'colorado', proj='bonne', param=45) # Show county indices on map map.text('county', 'colorado', proj='bonne', param=45, labels=paste(1:length(m$names))) #or perhaps map.text('county', 'colorado', proj='bonne', param=45, labels=paste(1:length(m$names)), col=1:length(m$names)) You can use your own labels vector above to show county abbreviations instead of full names, or other info, if desired. Once you get the mapping of the counties, you can connect to other sources of information. efg "Tord Snäll" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] Hi, I would like to plot a map of US counties using different colors. map() seems to be the function to use, e.g. library(maps); map('usa'); map('county', 'colorado', add=T,fill = T, col=c(1:5)) plots Colorado counties using colours 1 to 5. However, I want each color to represent a certain value - a value to be picked from a data frame. This code should show a correspoding map at the level of states: state.names <- system('tr "[A-Z]" "[a-z]"', state.name) map.states <- unix('sed "s/:.*//"', map(names=T,plot=F)) state.to.map <- match(map.states, state.names) color<- votes.repub[state.to.map, votes.year = 1900] / 100 map('state', fill=T, col=color); map('state', add=T) It is copied from page 6 in Richard A. Becker, and Allan R. Wilks, "Maps in S", AT&T Bell Laboratories Statistics Research Report [93.2], 1993. http://public.research.att.com/areas/stat/doc/93.2.ps I also wonder whether the county names are available in the database used by map(), and, if yes, how to extract or utilize them. Thanks! Tord ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.