Suggestion: Arrows is currently definded as: arrows(x0, y0, x1, y1, length = 0.25, angle = 30, code = 2, col = par("fg"), lty = NULL, lwd = par("lwd"), xpd = FALSE) length length of the edges of the arrow head (in inches). This definition is very rigid, the user has to convert inches on screen/paper to user coordinates. I would suggest to add a paramter "inches" like in "symbols": symbols(x, y, circles, squares, rectangles, stars, thermometers, boxplots, inches=TRUE, add=FALSE, fg=1, bg=NA, xlab = "", ylab = "", xlim = NULL, ylim = NULL, ...) inches If inches is FALSE, the units are taken to be those of the x axis. If inches is TRUE, the symbols are scaled so that the largest symbol is one inch in height. If a number is given the symbols are scaled to make largest symbol this height in inches. As for the geometric length of the arrow heads in "arrows" with the new parameter "inches": inches=FALSE: no problem (?) inches=TRUE: no problem (?) inches=<number>: no problem (?). Thanks for your consideration. -christian Dr.sc.math.Christian W. Hoffmann Mathematics and Statistical Computing Landscape Modeling and Web Applications Swiss Federal Research Institute WSL Zuercherstrasse 111 CH-8903 Birmensdorf, Switzerland phone: ++41-1-739 22 77 fax: ++41-1-739 22 15 e-mail: christian.hoffmann_at_wsl.ch__prevent_spamming www: http://www.wsl.ch/staff/christian.hoffmann/ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._