From: Greg Snow <Greg.Snow_at_imail.org>

Date: Mon, 14 Apr 2008 12:02:55 -0600

Date: Mon, 14 Apr 2008 12:02:55 -0600

OK, here is another approach.

Here is a function that will adjust the user coordinate system for you. You give it 2 points in the current coordinates (x1 and y1) and the values that you want the same 2 points to have in the new coordinate system (x2 and y2) and it will change the coordinate system to match:

update.usr <- function(x1,y1=NULL,x2,y2=NULL) {
xy1 <- xy.coords(x1,y1)

xy2 <- if( missing(x2) && missing(y2) ) {
xy.coords(y1)

} else {

xy.coords(x2,y2)

}

cur.usr <- par('usr')

xslope <- diff(xy2$x)/diff(xy1$x)

yslope <- diff(xy2$y)/diff(xy1$y)

new.usr.x <- xslope * ( cur.usr[1:2] - xy1$x ) + xy2$x new.usr.y <- yslope * ( cur.usr[3:4] - xy1$y ) + xy2$y

par(usr=c(new.usr.x, new.usr.y))

}

Here is an example of how to use it with your project:

> bp <- barplot(1:5)

x-coords of bar centers stored in 'bp'

> axis(1)

just to show what the current x-coordinates are

*>
*

> update.usr( bp[1:2], c(0,5), 1:2, c(0,20) )

adjust coordinate system so that bars 1 and 2 are centered at x vals of 1 and 2, and that the y range changes from 0-5 to 0-20.

> axis(3)

> axis(4)

show the new coordinate systems

*> x <- 1:5
**> y <- c(1,15,10,20,5)
**>
*

> lines(x,y, type='o', pch=16, cex=1.3)

add lines and points using the coordinates we want.

If your using 2 different y scales in the same plot, you should read through the discussions on this list that have appeared recently discussing the limitations/problems that can occur when using 2 different y scales in the same plot.

An improved version of this function will probably be included in a future version of the TeachingDemos package (unless someone shows me another existing function with the same capability, or Prof. Ripley writes a better version to include in a core package).

Hope this helps,

-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.snow_at_imail.org (801) 408-8111 ________________________________ From: Anne-Katrin Link [mailto:anne.link_at_gmx.de] Sent: Saturday, April 12, 2008 2:07 PM To: Greg Snow Cc: r-help_at_r-project.org Subject: Re: [R] two graphs in one figure? Dear Greg, thank you again for your help. The graph looks much better now. However, I need the bars to be assigned to the left y-axis, and the lines should be assigned to the right y-axis (the y-axes have different ranges,e.g. left y-axis 0-20, and right y-axis 0-1). Also would be nice if the bars had contour lines (more like the barplot)... would that be possible? Thank you so much again. Anne-Katrin ------------------------------------------------------------------------ -------------------------------- Barplot is probably not the best way here (it is possible, but more work than it is worth). Here is one approach that gives something similar to what you want: plot(x, y, lend=1, lwd=25, ylim=c(-1,10), xlim=c(0.75,5.25),type='h', col='grey') lines(x, y2) Is that good enough? or do you need the bars to look much more like the barplot? ________________________________ From: Anne-Katrin Link [mailto:anne.link_at_gmx.de] Sent: Sat 4/12/2008 7:11 AM To: Greg Snow Cc: r-help_at_r-project.org Subject: RE: [R] two graphs in one figure? Dear Greg, dear all, thank you for your reply! To clarify, here is an example of what I want to do (but better, of course!): x<- c(1,2,3,4,5) y<- 0:4 y2<- c(0,0,7,8,9) barplot(y ,ylim=c(-1,10), ylab="", xaxt="n",yaxt="n", main="") axis(4,at=c(1,2,3,4,5,6)) text(6,2.9, "2nd y-axis", srt = 270, xpd = TRUE) par(new=TRUE) plot(x, y2, lty=2,type="l", xlab="x-axis", ylab= "y-axis") I dont think "barplot" is the right thing to use here since I cant specify the x-values....what can I do to make this graph look better? Regards, Anne-Katrin Using par(new=TRUE) can be tricky. A better approach is to create one plot, then add the other information to it. You can add bars to an existing graph using barplot with add=TRUE, you can add lines to an existing plot using the lines function. If you give more detail of what you want (examples of x, y, and ynew) then we may be able to give more help. ________________________________ From: r-help-bounces_at_r-project.org on behalf of Anne-Katrin Link Sent: Thu 4/10/2008 7:18 AM To: R Help Subject: [R] two graphs in one figure? Dear all, how can I plot a line graph and a bar graph in one single figure? I tried to combine "barplot" and "plot". Even though they both have the same x-values (1 to 55), it just doesnt look as if they match in their scale (the barplot is much wider than the "plot"....even though I tried to put limits on the x-axis). Here is an example of what I did: barplot(y, xaxt="n",yaxt="n",ylim=c(-1,45), xlim=c(1,55)) ... par(new=TRUE) plot(x, ynew, lty=2, type="l", ylim=c(0,15), xlim=c(1,55)) Another question: how can I make sure that the "0"-values from the barchart are displayed as well? Thank you so much! Anne-Katrin -- GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen! Jetzt dabei sein: http://www.shortview.de/?mc=sv_ext_mf@gmx [[alternative HTML version deleted]] ______________________________________________ R-help_at_r-project.org 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.Received on Mon 14 Apr 2008 - 18:05:34 GMT

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