Thanks everyone for your comments and help. Actually, I found my mistake (probably stupid for y'all). I was drawing first the heatmap and then putting the >png("heatmap.2.png").
What you have to do is : >a<- read.csv (".... .csv) >a_matrix <- data.matrix (a) >row.names(a_matrix) <-a$Name # In my case I wanted to have the name from the column Name... >a_matrix <-a_matrix [,2:5] # To delete the first column containing the Name. >library(gplots) >png("heatmap.2.png", width= 10000, height = 10000, units = "px", bg="white") >heatmap.2(a_matrix, Rowv=NA, Colv = NA, col= topo.colors(250), scale=column, margins=c(7,10), trace="none", density.info=c("none")) The only problem I have now, is taht I get a nice png file of 2Mb, but I can't read the name of the genes anymore.!! 2 questions : 1) Do I need to play with the "pointsize = " 2) What is the higher quality picture I can make ? When I try with more pixels "R " tends to crash... THANKS Fred -- View this message in context: http://r.789695.n4.nabble.com/how-to-save-a-heatmap-2-in-png-jpeg-tiff-tp4642607p4642641.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.