> The contour lines are actually useful to see groupings. > However w/o a legend for density it is not possible to see what is > presented.
I need to re-iterate, that the diagonal lines, may be important. Also, I'm not sure I see the point in adding density values. Unless people have a good knowledge of probability theory and calculus, I doubt that specific density values will be useful. i.e. If I said the density was 0.0035, what does that tell you...? If you really want to add a legend, it's possible. But this creates at least two problems: (1) In the base graphics system, the resulting plots can't be nested. (2) It's difficult to interpret specific color-encoded values. In my opinion, a better idea, is to label the contour lines. In my packages, this is possible by using contour.labels=TRUE, however, the defaults are ugly. (Something else for my todo list). Here's a slightly more complex example, with prettier contour labels: library (barsurf) library (KernSmooth) set.bs.theme ("heat") plot_ds <- function (dataset, main="", xlim, ylim, ..., ncontours=3, labcex=0.8, ndec=3, k1=1, k2=1, n=30) { names <- names (dataset) x <- dataset [,1] y <- dataset [,2] bw.x <- k1 * bw.nrd (x) bw.y <- k2 * bw.nrd (y) if (missing (xlim) ) xlim <- range (x) + c(-1, 1) * bw.x if (missing (ylim) ) ylim <- range (y) + c(-1, 1) * bw.y ks <- bkde2D (dataset, c (bw.x, bw.y), c (n, n), list (xlim, ylim), FALSE) fb <- seq (min (ks$fhat), max (ks$fhat), length.out = ncontours + 2) fb <- fb [2:(ncontours + 1)] fb <- round (fb, ndec) plot_cfield (ks$x1, ks$x2, ks$fhat, contours=FALSE, main=main, xlab = names [1], ylab = names [2], xyrel="m") points (x, y, pch=16, col="#00000040") contour (ks$x1, ks$x2, ks$fhat, levels=fb, labcex=labcex, add=TRUE) } plot_ds (bat_call, "plot 2", c (25, 28), c (-15, 10), k1=1.25, k2=1.25) If you still want a legend, have a look at: graphics::filled.contour And then modify the second half of my code, starting after ks <- ... ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.