Sander Oom wrote: > Dear R users, > > In order to illustrate the possible effects of events on variables > plotted against time, I would like plot a time line of events along side > the plot of the variables. > > The x-axis should be some time unit; the y-axis should be the variable > of interest; the time line should be plotted below the graph along the > same x-axis scale. > > As I have many variables and different events lists, I would like to > write a script to read the events from a file and plot them together > with the other plot. > > The time line should look something like this: > http://www.oslis.k12.or.us/secondary/howto/organize/images/timeline.gif > Here's one way:
# some fake data please, maestro fakedata<-sample(1:10,10) # leave a bit of extra space beneath and to the left of the plot par(mar=6,6,4,2) # this function will probably end up in the "plotrix" package time.line<-function(x,y,at=NULL,labels=TRUE,tlticks=NULL,...) { if(missing(x) && missing (y)) stop("Usage: time.line(x,y,at=NULL,labels=TRUE)") plotrange<-par("usr") # get the graphical parameters oldpar<-par(no.readonly=TRUE) # turn off clipping par(xpd=TRUE) if(missing(x)) { # it's a horizontal line segments(plotrange[1],y,plotrange[2],y,...) ticklen<-(plotrange[4]-plotrange[3])*0.02 if(!is.null(tlticks)) segments(tlticks,y+ticklen,tlticks,y-ticklen,...) mwidth<-strwidth("M") # blank out the line where labels will appear rect(at-mwidth,y-ticklen,at+mwidth,y+ticklen,col="white",border=FALSE) # rotate the text par(srt=90) # draw the labels text(at,y,labels,...) } if(missing(y)) { # it's a vertical line # draw the line segments(x,plotrange[3],x,plotrange[4],...) ticklen<-(plotrange[2]-plotrange[1])*0.02 if(!is.null(tlticks)) segments(x+ticklen,tlticks,x-ticklen,tlticks,...) mheight<-strheight("M") # blank out the line where labels will appear rect(x-ticklen,at-mheight,x+ticklen,at+mheight,col="white",border=FALSE) # draw the labels text(x,at,labels,...) } # restore the parameters par(oldpar) } # create a file with the positions and labels you want like this: # 2.5,first # 4,second # 7,third # 8.5,fourth # call it "labels.txt" and read it in tl.labels<-read.table("labels.txt",sep=",") plot(fakedata,xlab="") # display a horizontal time line time.line(x=-1,at=tl.labels[[1]],labels=tl.labels[[2]],col="black") # now a vertical one time.line(y=-1,at=tl.labels[[1]],labels=tl.labels[[2]],col="black") ______________________________________________ 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