Thank you very much

I'll try this 

Meytar

 

From: Brian Diggs [via R]
[mailto:ml-node+3415433-1829104127-202966@n4.nabble.com] 
Sent: Tuesday, March 29, 2011 6:46 PM
To: meytar
Subject: Re: plotting several ROC curves on the same graph

 

On 3/29/2011 2:48 AM, meytar wrote: 


> Hello 
> I am trying to make a graph of 10 different lines built each from 4 
> different 
> segments and to add a darker line that will represent the average of all 
> graphs 
> - all in the same plot.Actually each line is a ROC plot 
> The code I'm using for plotting one line is as follows: 
> 
> logit.roc.plot<- function(r, title="ROC curve") { 
> old.par<- par(no.readonly = TRUE); on.exit(par(old.par)) 
> par(xaxs="i", yaxs="i") 
> plot(1 - r$spec, r$sens, xlim=c(0, 1), ylim=c(0,1), type="l", 
> xlab="(1 - specificity): false positive rate", 
> ylab="sensitivity: true positive rate", 
> col="grey82", lwd=2); 
> points(1 - r$spec, r$sens,pch=20, cex=1.5, col="grey82") 
> abline(0, 1, lty=2); 
> segments(1-r$spec, 1-r$spec, 1-r$spec, r$sens, lty=3) 
> #text(1 - max(r$spec,na.rm=T), 
> r$sens[which.max(r$spec)],r$pts[which.max(r$spec)],pos=2,cex=0.8) 
> text(0, 0.9, paste("Area under ROC:",round(logit.roc.area(r),4)), pos=4) 
> title(main = title) 
> } 
> r[5,]=c(0,0,1,10) 
> logit.roc.plot(r) 
> r=r[-5,] 
> text(1 - max(r$spec,na.rm=T), 
> r$sens[which.max(r$spec)],r$pts[which.max(r$spec)],pos=2,cex=0.8) 
> 
> while r is  a MATRIX (4x4) with 
> colnames=c("pts",sens","spec",iterationnumber.") 
> and I have for each ROC curve a different matrix but all matrices have the

> same 
> size. (They are organized as a list of 10 matrices by the size 4X4 each) 
> 
> Would appreciate your help in putting all ROC curves on the same plot. 
> Thank you 


The reason you are getting new plots each time is the plot() call in the 
function.  If you pull the plot initialization out of the function (so 
that the limits and axis labels get set up only once), then that plot 
could be replaced with a points call. 

-- 
Brian S. Diggs, PhD 
Senior Research Associate, Department of Surgery 
Oregon Health & Science University 

______________________________________________ 
[hidden email] 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. 



  _____  

If you reply to this email, your message will be added to the discussion
below:

http://r.789695.n4.nabble.com/plotting-several-ROC-curves-on-the-same-graph-
tp3414263p3415433.html 

To unsubscribe from plotting several ROC curves on the same graph, click
here
<http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by
_code&node=3414263&code=bWV5dGFyQHR4LnRlY2huaW9uLmFjLmlsfDM0MTQyNjN8NzgxMTk0
Mzk3> . 



--
View this message in context: http://r.789695.n4.nabble.com/plotting-several-ROC-curves-on-the-same-graph-tp3414263p3415569.html
Sent from the R help mailing list archive at Nabble.com.
	[[alternative HTML version deleted]]

