Dear Alok, Maybe you should consider converting the im data to sp class. Then, you have as many grids in a single SpatialGridDataFrame e.g.:
> library(maptools) > library(rgdal) > grids <- as(bei.extra[[1]], "SpatialGridDataFrame") > names(grids)[1] <- "elev" > grids$grad <- as(bei.extra[[2]], "SpatialGridDataFrame")$v > spplot(grids["elev"]) ... > grids$achan <- readGDAL("achan.asc")$band1 > save(grids, "grids.image") see also: http://spatial-analyst.net/wiki/index.php?title=Species_Distribution_Modelling HTH, T. Hengl > -----Original Message----- > From: r-sig-geo-boun...@stat.math.ethz.ch > [mailto:r-sig-geo-boun...@stat.math.ethz.ch] On Behalf > Of Alok K. Bohara, PhD > Sent: Wednesday, January 07, 2009 4:21 PM > To: Greg Lee > Cc: r-sig-geo@stat.math.ethz.ch > Subject: Re: [R-sig-Geo] combining two image files into one database > > Thanks Greg for your response: > > I want to do what the examples in Spatstat do with regard to the point > and pixel/image data bei and bei.extra.. (bei.extra contains a list of > two image files --elevation and gradient. They plot these two items > (and also take log, I believe) > > In my case: > > X_image > Y_image > > (I converted both from text matrix to pixel/image using "im(...)" command) > > I want to combine (or list) X_image and Y.image as a part of a single > file -- XY_image, and save and do the following > > load("XY.image") > > plot(XY_image) # plot both images side by side > plot(XY_image$X_image) # plot just the X_image > etc... > > Thank you for your help. > > ######### > > I tried doing the list command: > XY_image <-list(X_image,Y_image) > > but it returns NULL when I do "XY$X_image" > > Sincerely, > Alok Bohara > > > > > > Greg Lee wrote: > > Hello Alok, > > > > We really need more details about what you are trying to acheive in > > order to help you. > > > > c(X, Y) concatenates the objects X and Y. The result will be a vector. > > If X and Y happen to be m x n matrices, the result will be a vector of > > length 2 * m * n: probably not what you want. > > > > You can see this for yourself. Eg: > > > > X <- matrix(1, 3, 3) > > Y <- matrix(2, 3, 3) > > c(X, Y) > > > > If you were hoping to combine the information in corresponding pixels > > of the matrices X and Y, you will need to have a clear idea of *how* > > you would like the information to be combined. ie: Are you looking for > > the mean value of the pixels, or is some other operation required? > > > > Eg 2: > > > > X <- matrix(1:9, 3, 3) > > Y <- matrix(2, 3, 3) > > X + Y / 2 > > > > Hope that helps. > > > > Greg > > > > > > 2009/1/7 Alok K. Bohara, PhD <boh...@unm.edu <mailto:boh...@unm.edu>> > > > > Hi: > > > > Let me start by saying that I am new to R. I converted two pixel > > ascii matrices into image files: > > > > X_im <- im(X) # X is an ascii pixel matrix > > Y_im <- im(Y) # Y is an ascii pixel matrix > > > > How can I combine these two images into 1) one datafile "XY_im", > > 2) save it and 3) read it after loading (e.g., x <- XY_im$X_im. > > and plot it.) > > > > I tried doing this: > > > > XY_im <- c(X_im,Y_im) > > save(XY _im, file = "XM_im.Rdata") > > load("XY_im.Rdata") > > x<- XY_im$X_im # It does not like $ and says it is atomic > > something... > > plot(x) # of course it does not work either. > > > > What am I doing wrong? Any tips? > > > > Thanks you. > > > > Alok Bohara > > > > > > -- > > Alok K. Bohara, Ph.D. > > Professor > > Department of Economics > > University of New Mexico > > Albuquerque, NM 87131,USA > > Ph: 505-277-5903/5304(w) > > Fax:505-277-9445 > > email: boh...@unm.edu <mailto:boh...@unm.edu> > > http://www.unm.edu/~econ/faculty/professors.html > > <http://www.unm.edu/%7Eecon/faculty/professors.html> > > Nepal Study Center: http://nepalstudycenter.unm.edu > > <http://nepalstudycenter.unm.edu/> > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@stat.math.ethz.ch <mailto:R-sig-Geo@stat.math.ethz.ch> > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > > > > -- > Alok K. Bohara, Ph.D. > Professor > Department of Economics > University of New Mexico > Albuquerque, NM 87131,USA > Ph: 505-277-5903/5304(w) > Fax:505-277-9445 > email: boh...@unm.edu > http://www.unm.edu/~econ/faculty/professors.html > Nepal Study Center: http://nepalstudycenter.unm.edu > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo