Thanks for this example. I have since found the 'arrows' function which is not as comprehensive as rayplot but seems to work well for basic vector field plots, e.g.
y <- rep(1:5,rep(5,5)) x <- rep(1:5,5) x1 <- x-sqrt(x*x + y*y)/25 y1 <- y-2*x/125 plot(x,y,,main='Sample Vector Plot',type='n') arrows(x,y,x1,y1,length=0.1) --Rich Richard Kittler AMD TDG 408-749-4099 -----Original Message----- From: joerg van den hoff [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 09, 2004 4:10 AM Cc: Kittler, Richard; [EMAIL PROTECTED] Subject: Re: [R] Is there an R-version of rayplot maybe this q&d try helps? #=================cut herer============= vectorplot <- function (field) { #input is a (N x 4 array) of N vectors: # field[,1:2] - x/y position of vectors # field[,3:4] - x/y componnent of vectors # plotted are the 2-D vectors attached to the specified positions if (is.null(dim(field))||dim(field)[2] != 4) stop("N x 4 array expected") loc <- field[,1:2] val <- field[,3:4] alpha <- rbind(loc[,1],loc[,1]+val[,1]) omega <- rbind(loc[,2],loc[,2]+val[,2]) matplot(alpha,omega,type='l',lty=1,col='black') #the vector lines points(loc) #the start points points(loc+val,pch=20) #the end points } #example: loc=matrix(rnorm(100),50,2) field <- cbind(loc,loc) vectorplot(field) #=================cut herer============= there are no nice arrow heads, of course, but one could construct some... for now, vectors start with open circles and end with filled circles. joerg ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html