Dear Francesc, This is rather easy to do with the ggplot2 package.
library(ggplot2) dataset <- expand.grid(x = 1:10, y = 1:50) dataset$z <- runif(nrow(dataset)) ggplot(data = dataset, aes(x = x, y = y, fill = z)) + geom_tile() + scale_fill_gradient(low="white", high="black") + coord_equal() Have a look at the ggplot2 website (http://had.co.nz/ggplot2/) for more examples. HTH, Thierry ---------------------------------------------------------------------------- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 [EMAIL PROTECTED] www.inbo.be Do not put your faith in what statistics say until you have carefully considered what they do not say. ~William W. Watt A statistical analysis, properly conducted, is a delicate dissection of uncertainties, a surgery of suppositions. ~M.J.Moroney -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Namens Francesc Montané Verzonden: vrijdag 18 januari 2008 12:01 Aan: r-help@r-project.org Onderwerp: [R] Problems with lattice plot Hello useRs, I have some problems when I try to plot a lattice. The lattice has 200 columns (X value) and 5 rows (Y value), with a total of 1000 squares. I want to plot this lattice with the squares having different colours according to a variable value. The variable I want to plot is cover value of a shrub, and it has values between 0 and 1. I want to plot the squares with value 1, black, the squares with values 0, white, and the values between 0 and 1 with grey, more or less dark depending on its proximity to 1 (dark grey) or 0 (light grey). I have tried this: plot(x=transect41$x,y=transect41$y,asp=1, xlab="",ylab="", axes=F,pch=22,cex=1.01,lwd=0.05, bg=gray(1-transect41$CoverValue),col=gray(0.75)) plot(pch=22,cex=1.01,lwd=0.05) When I plot the lattice, I have problems because the squares have different sizes. Moreover, some of them look like a rectangle and not a square. What can I do to solve this problem? Many thanks in advance. Francesc ______________________________________________ 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. ______________________________________________ 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.
