Christoph, I see two problems:
(1) use plot(x,y,pch=16,xlim=c(0,10),asp=1), as the default has the x/y scales different. (2) It looks to me that the expression "srt=180/pi*atan(slope)" should be "srt=180*atan(slope)/pi" Regards, Tom Dr. Christoph Scherber wrote:
Dear all, I stumbled over a problem recently when trying to use srt with text() on a windows device. What I intended to do was to plot a simple regression line, and to rotate a piece of text such that the text has the same angle as the regression line. However, the text is always plotted in a slightly wrong angle: #### x=1:10 #create arbitrary x and y values y=x*2-rnorm(1:10) plot(x,y,pch=16,xlim=c(0,10)) #create the graph abline(lm(y~x)) #calculate the y coordinate of the text: yval=predict(lm(y~x),list(x=rep(2,length(x))))[1] #calculate the slope: slope=as.numeric(lm(y~x)[[1]][2]) text(2,yval,"Regression",srt=180/pi*atan(slope),adj=0) #### What am I doing wrong here? Many thanks in advance for any help! Best wishes Christoph (using R 2.6.1 on Windows XP) ______________________________________________ R-help@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.
-- Thomas E Adams National Weather Service Ohio River Forecast Center 1901 South State Route 134 Wilmington, OH 45177 EMAIL: [EMAIL PROTECTED] VOICE: 937-383-0528 FAX: 937-383-0033 ______________________________________________ R-help@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.
