Dear All, Someone suggesting me to?use the filled.contour function to plot the image together with the color index, and?an example?from the help menu is show below. ? ################################################################################# require(grDevices) # for colours filled.contour(volcano, color = terrain.colors, asp = 1)# simple x <- 10*1:nrow(volcano) y <- 10*1:ncol(volcano) filled.contour(x, y, volcano, color = terrain.colors, ??? plot.title = title(main = "The Topography of Maunga Whau", ??? xlab = "Meters North", ylab = "Meters West"), ??? plot.axes = { axis(1, seq(100, 800, by = 100)) ????????????????? axis(2, seq(100, 600, by = 100)) }, ??? key.title = title(main="Height\n(meters)"), ??? key.axes = axis(4, seq(90, 190, by = 10)))# maybe also asp=1 ################################################################################# ? I am still trying to draw several gridlines with 10m gaps, which might represent the height of the mountain on the image but still can't manage it. ? Could someone please give some hints? ? Thank you Fir