Ravi Ramaswamy <raram...@gmail.com> writes: > I am using pls package for some pcr computations. There is a data set called > gasoline. > > Would someone be able to tell me what command(s) could be used to produce > this graph in R?
I presume you are talking about Figure 1 in the pls article in R news 2006/3 [1]. The plot was produced with the following commands: data(gasoline) par(mar = c(2, 4, 1, 0) + 0.1) matplot(t(gasoline$NIR), type = "l", ylab = "log(1/R)", xaxt = "n") ind <- pretty(seq(from = 900, to = 1700, by = 2)) ind <- ind[ind >= 900 & ind <= 1700] ind <- (ind - 898) / 2 axis(1, ind, colnames(gasoline$NIR)[ind]) > I am not sure where the log(1/R) - Y-axis - are coming from The measurements in the NIR matrix are log(1 / reflectance), hence the label "log(1/R)". This is how the data was published by Kalivas [2], and is a standard way of representing Near Infrared Reflectance measurements. [1] http://cran.r-project.org/doc/Rnews/Rnews_2006-3.pdf [2] J. H. Kalivas. Two data sets of near infrared spectra. Chemometrics and Intelligent Laboratory Systems, 37: 255–259, 1997. -- Regards, Bjørn-Helge Mevik ______________________________________________ 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.
