Re: [R] overlaying a set of 'grouping' lines on a plot from image()

Try this: # define the locations on the x axis for each cell in the image nxcells <- dim(m)[2] xlocs <- (seq(nxcells)-1)/(nxcells-1) # define the groupings group <- rep(1:3, c(10, 20, 25)) # calculate the range of locations on the xaxis for each group group.ranges <- sapply(split(xlocs, group),

[R] overlaying a set of 'grouping' lines on a plot from image()

Hi, I have a matrix that I am displaying via image. I would like to obtain an image where the columns are 'grouped' (I have a grouping variable). But I am not sure how how I can draw the lines to indicate the grouping in the margin. I realize this is essentially waht heatmap does but as I have a se