Thanks a lot! That worked. I have two R related questions when I use the store<-readGDAL(fname='lena256.bmp') this returns the struct below
> str(store) Formal class 'SpatialGridDataFrame' [package "sp"] with 6 slots ..@ data :'data.frame': 65536 obs. of 1 variable: .. ..$ band1: int [1:65536] 255 255 255 255 255 255 255 255 255 255 ... ..@ grid :Formal class 'GridTopology' [package "sp"] with 3 slots .. .. ..@ cellcentre.offset: Named num [1:2] 0 -722925 .. .. .. ..- attr(*, "names")= chr [1:2] "x" "y" .. .. ..@ cellsize : num [1:2] 2835 2835 .. .. ..@ cells.dim : int [1:2] 256 256 ..@ grid.index : int(0) ..@ coords : num [1:2, 1:2] 0 722925 -722925 0 .. ..- attr(*, "dimnames")=List of 2 .. .. ..$ : NULL .. .. ..$ : chr [1:2] "x" "y" ..@ bbox : num [1:2, 1:2] -1418 -724342 724342 1418 .. ..- attr(*, "dimnames")=List of 2 .. .. ..$ : chr [1:2] "x" "y" .. .. ..$ : chr [1:2] "min" "max" ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots .. .. ..@ projargs: chr NA How the "R" when I run image(store) plots the lena correct. Where it store how the file was originally? Also when I do str(as.matrix(store)) this takes only the data and transforms them to the original matri str(as.matrix(store)) int [1:256, 1:256] How it does that? Looks as "magic" to me.... B.R Alex ________________________________ From: Michael Sumner <mdsum...@gmail.com> Cc: "R-help@r-project.org" <R-help@r-project.org> Sent: Thursday, November 24, 2011 2:25 PM Subject: Re: [R] readGDAL or raster for reading bit map files Just do m <- as.matrix(store) or m <- as.image.SpatialGridDataFrame(store)$z image(m) They give the same result with different orientations. Note that both assume a single-band raster, e.g. you only have a "greyscale" bitmap (for example). The details behind all this is given in the documentation for the sp package. See ?image for the basic image plot for a matrix. Cheers, Mike. > Dear all, > I have asked yesterday of how I can read a simple bitmap file in R cran. > > I was suggest to use either readGDAL or raster for loading my bitmap > > > a. I have done it with readGDAL like > > store<-readGDAL(fname='lena256.bmp') > and it works,... but it converts my matrix-like notion of a bitmap to a > large vector > > b. Raster also returns a class that I can not understand. > > So 1, I want to load it and keep the image as a matrix (so every cell in the > matrix will correspond to a pixel) > 2. I want to be able to plot the image based on that matrix that I have > loaded too. > > Could you please explain me how I can do those? > > B.R > Alex > > [[alternative HTML version deleted]] > > > ______________________________________________ > 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. > > -- Michael Sumner Institute for Marine and Antarctic Studies, University of Tasmania Hobart, Australia e-mail: mdsum...@gmail.com [[alternative HTML version deleted]]
______________________________________________ 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.
