Daisy Englert Duursma
2010-Sep-06 01:05 UTC
[R] colorRamp of image to span larger range than dataset
Hello and thanks in advance, Using the dataset volcano: ascols = colorRampPalette(c("gray","yellow","darkgoldenrod1","orange","red"),interpolate="spline") x <- 10*(1:nrow(volcano)) y <- 10*(1:ncol(volcano)) image(x, y, volcano, col = ascols, axes = FALSE) In the example above, how would I change my colorRampPalette or image function so that it would span to 300 even though max(volcano) = 195? The image I want to make should not return any red because it does not reach the true maximum possible value which is 300. Thanks, Daisy -- Room E8C156 Dept. Biological Sciences Macquarie University? NSW? 2109 Australia
Bill.Venables at csiro.au
2010-Sep-06 01:21 UTC
[R] colorRamp of image to span larger range than dataset
colorRampPalette returns a function, not a list of colours. You might want to try something like: ascols <- colorRampPalette(c("gray", "yellow", "darkgoldenrod1", "orange", "red"), interpolate="spline") x <- 10*(1:nrow(volcano)) y <- 10*(1:ncol(volcano)) image(x, y, volcano, col = ascols(300), axes = FALSE) ### spot the difference... -----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Daisy Englert Duursma Sent: Monday, 6 September 2010 11:05 AM To: r-help at r-project.org Subject: [R] colorRamp of image to span larger range than dataset Hello and thanks in advance, Using the dataset volcano: ascols = colorRampPalette(c("gray","yellow","darkgoldenrod1","orange","red"),interpolate="spline") x <- 10*(1:nrow(volcano)) y <- 10*(1:ncol(volcano)) image(x, y, volcano, col = ascols, axes = FALSE) In the example above, how would I change my colorRampPalette or image function so that it would span to 300 even though max(volcano) = 195? The image I want to make should not return any red because it does not reach the true maximum possible value which is 300. Thanks, Daisy -- Room E8C156 Dept. Biological Sciences Macquarie University? NSW? 2109 Australia ______________________________________________ R-help at 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.