similar to: overlay two pixmap

Hi, I'm having trouble writing .pnm images which I think is due to a problem with my colour space. The pixmap object seems to be looking for 72 of 8 colours (one per cell?) which doesn't seem healthy... > library(pixmap) > x <- pixmapIndexed(rep(1:8, 9), nrow=6, col=rainbow(8)) > x Pixmap image Type : pixmapIndexed Size : 6x12 Resolution : 1x1

Dear R users I have a two-dimensional array, whose values I want to plot, using the pixmapGrey class. Plotting works fine, and now I would like to be able to identify some of the points in the plot using identify(). But I get the following message while pressing the left mouse button: > plot(pixmapGrey(fmri.vtc[,,slice,volume])) > identify(fmri.vtc[,,slice,volume]) warning: no point with

Hi R users: I got the following message when I use the pixmap library on R 1.7.0 over w2K platform (on R 1.6.2 it runs right). pixmapGrey(matrix(c(0,1),128,128)) Error in .class1(object) : Object "from" not found I download the library .zip file from: http://cran.r-project.org/bin/windows/contrib/1.7/pixmap_0.3-2.zip Other question: When I try to "Install package(s) from

am I right in the assumption, that for calculation of the condition numbers I have to use the correlation matrix of X, and not t(x) %*% x? > e <- eigen(t(x) %*% x) better (x must not have a first column of ones): > e <- eigen(cor(x)) > e$val [1] 6.6653e+07 2.0907e+05 1.0536e+05 1.8040e+04 2.4557e+01 2.0151e+00 > sqrt(e$val[1]/e$val) [1] 1.000 17.855 25.153 60.785 1647.478

Hi All, I have a greyscale image that I am reading in through RGDAL and placing in a pixmap object. As an example use the logo.jpg file that comes with the RGDAL package: #Read the file logo <- system.file("pictures/logo.jpg", package="rgdal")[1] x <- new("GDALReadOnlyDataset", logo) #Create the pixmap object xGrey <- getPixmapGDAL(x) Now I would

I am just about working through Faraways excellent tutorial "practical regression and ANOVA using R" on page 24 he makes the x matrix: x <- cbind(1,gala[,-c(1,2)]) how can I understand this gala[,-c(1,2)])... I couldn't find an explanation of such "c-like" abbreviations anywhere. thanks for a hint. another problem: I couldn't load the faraway library, using the

Christoph -- There was just a thread on this earlier this week. You can search in the archives for the title: "refitting lm() with same x, different y". (Actually, it doesn't turn up in the R site search yet, at least for me. But if you just go to the archive of recent messages, available through CRAN, you can search on refitting and find it. The original post was from William

Hi I use pixmapIndexed tmp.vimp <- array(0,c(x.dim,y.dim)) tmp.vimp <- pixmapIndexed(tmp.vimp, col=rainbow) to plot values of a 2D matrix. I 'fill' the pixmapIndexed like: for (x in 1:x.dim) { for (y in 1:y.dim) { tmp.vimp at index[x,y] <- my.matrix[x,y] }} how can I define, that the colors are painted e.g. according the rainbow

Hola! I will want to identify pixels in an image with the mouse, for so getting the image data from the matrix(es), for use in subsequent discriminant analysis. But the following bombs R: (windows XP, rw1071) > str(baboon) list() - attr(*, "size")= int [1:2] 512 512 - attr(*, "cellres")= num [1:2] 1 1 - attr(*, "bbox")= num [1:4] 0 0 512 512 - attr(*,

I hope this question is adequate for this list I use the nnet code from V&R p. 348: The very nice and general function CVnn2() to choose the number of hidden units and the amount of weight decay by an inner cross-validation- with a slight modification to use it for classification (see below). My data has 2 classes with unequal size: 45 observations for classI and 116 obs. for classII With

Sorry, I am sure, this must be documented somewhere (but there are that many docs and tutorials to scan for topics..., actually a great thing... but if you are in a hurry..): I want to save a plot as .ps (or .eps): > postscript("plot1.eps", horizontal=FALSE, onefile=FALSE,height=8,width=8,pointsize=10) > plot(hpfit$fit,rstudent(hpfit),xlab="Fitted

Dear all, I try to figure out how to use R to count the number of pixels of the same color in some gray-level picture. I managed to read it in either tiff or jpeg format, but the returned pixmap object keeps its information out of (my) reach. Is there an easy way to tabulate the different color/graylevel pixels and their numbers? Or should I use a completely different (free) software?

again, under another subject: sorry, maybe an all too trivial question. But we have power data from J frequency spectra and to have the same range for the data of all our subjects, we just transformed them into % values, pseudo-code: power[i,j]=power[i,j]/sum(power[i,1:J]) of course, now we have a perfect linear relationship in our x design-matrix, since all power-values for each subject sum up

Hi, dear R pros I try to understand eigen(). I have seen, that eigen() gives the eigenvectors normalized to unit length. What shall I do to get the eigenvectors not normalized to unit length? E.g. take the example: A [,1] [,2] V1 0.7714286 -0.2571429 V2 -0.4224490 0.1408163 Calculating eigen(A) "by hand" gives the eigenvectors (example from Backhaus,

Hi, I ran into the following peculiarity involving S4 method dispatch and namespaces. I develop a package which have a namespace and which depends on 'pixmap' package, which itself does not have a namespace. Now, in my package I have a class which has a slot for objects from class "pixmap" and I want to have a "plot" method for this new class. Not to clutter the

Dear list, here is a problem I met when trying to use a method for an S4 object, without loading the package in which the method was defined. I do not know if this is a bug, or a mistake of mine. Normally, I think the package in which the appropriate method is defined is loaded automatically when calling the method. The problem is that if the package is indeed loaded automatically, the

Dear all, I have been trying to speed up a process we have been done in ArcGIS. We have to read a single layer TIFF (monochrome image) in . For this, I have used the "rtiff" package. After reading the TIFF file, I compared the raw values for each pixel that I have in ArcGIS to the ones obtained in R. In ArcGIS I have discrete values in the range 0..255, while in R I have continuous

Hi, my name is Ellen. I want to ask you about R Code. I got a code for extracting a pixel value, but I can't compile it..  It is said "Error in is.data.frame(x) : object 'lena' not found" Here is the original full code: library(pixmap) lena <- read.pnm("oldlennablur.pgm") write.table(lena@grey,"mylenna", quote=FALSE, row.names = FALSE, col.names=

Dear R-users, dear Prof. Ripley as package maintainer I tried to investigate the odd error, when I call nnet together with a 'weights' parameter, using the 'fgl' example in V&R p 348 The error I get is: Error in eval(expr, envir, enclos) : Object "w" not found I think it is a kind of scoping problem, but I really cannot see, what the problem exactly is. and

Dear R-users I use nnet for a classification (2 classes) problem. I use the code CVnn1, CVnn2 as described in V&R. The thing I changed to the code is: I define the (class) weight for each observation in each cv 'bag' and give the vector of weights as parameter of nnet(..weights = weight.vector...) Unfortunately I get an error during some (but not all!) inner-fold cv runs: