If I have a contourplot (in the lattice package) and I want to add straight lines to it, how do I do this?
I see that there are llines() and lsegement() functions for lattice plots, but they don't seem to do anything in this case: library(lattice) library(KernSmooth) x=rnorm(10000) y=x+rnorm(x,0,.5) a=bkde2D(cbind(x,y),.7) z=as.vector(a$fhat) grid=expand.grid(x=a$x1,y=a$x2) grid$z=z contourplot(z~x*y,data=grid,region=T,col.regions=gray(seq(1,0,len=255)),colorkey=T,cuts=50,contour=F) llines(x=c(-5,5),y=c(-5,5)) > NULL lsegments(x0=-5,y0=-5,x1=5,y1=5) I'm just trying to do the equivalent of abline(0,1) on the plot. ltext(), on the other hand, seems to like to place text in the upper left corner of the plot. I suspect that I misunderstand the coordinate system that lattice uses for contour plots. Can anyone enlighten me? Richard -- Richard D. Morey, M.A. Research Assistant, Perception and Cognition Lab University of M issouri-Columbia ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.