[R] Time line plot in R?

[Sander Oom]

Jim,

Brilliant! Thought someone might have figured it out already. Now we 
just need a gallery to show off this graph!

One little thing: the par(mar=6,6,4,2) gives an error:

'Error in par(args) : parameter "mar" has the wrong length'

Any suggestions?

Code below includes fake labels for testing.

Cheers,

Sander.


# 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=270)
   # 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)
}

# some fake labels
eventT<-c(2.5, 4, 7, 8.5)
eventD<-c("first event","second event","third event","fourth event")
tl.labels<-data.frame(eventT,eventD)

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")


 > version
          _
platform i386-pc-mingw32
arch     i386
os       mingw32
system   i386, mingw32
status
major    2
minor    0.1
year     2004
month    11
day      15
language R
 >

Jim Lemon wrote:
> 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")
> 
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