The EBImage package from bioconductor will read image files (png and others), the object read has a slot called .Data that is a 3 dimensional array with one dimension being the color (red,green,blue), so you could just grab one of those 3 layers and it would probably be what you want (or some function of that layer, or combination of the 3 layers).
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Beutel, Terry S > Sent: Thursday, May 19, 2011 10:02 PM > To: Barry Rowlingson > Cc: r-help@r-project.org > Subject: Re: [R] Converting the graphics window to a data matrix > > Thanks Barry. I have now got as far as creating the png (or gif or > tiff) images (as per your suggestions). But I am unable to work out how > to convert each to a 2 dimensionional numeric matrix showing the > spatial distribution of occupied/unoccupied pixels in R. Any > suggestions anybody? > Thanks > > Terry > > -----Original Message----- > From: b.rowling...@googlemail.com [mailto:b.rowling...@googlemail.com] > On Behalf Of Barry Rowlingson > Sent: Thursday, 19 May 2011 4:19 PM > To: Beutel, Terry S > Cc: r-help@r-project.org > Subject: Re: [R] Converting the graphics window to a data matrix > > On Thu, May 19, 2011 at 5:19 AM, Beutel, Terry S > <terry.beu...@deedi.qld.gov.au> wrote: > > I'm wondering if anyone is aware of a way to take what is visible in > > the R graphics window, pixelate it, and express that pixellation in a > > numeric matrix. For example, I am using the following command to > > create a black (present) and white (absent) spatial simulation of > > grass tussock distribution. > > > >> > > symbols(x=runif(100,-.5,1.5),y=runif(100,- > .5,1.5),circles=runif(100)/3 > > 0, > > inches=F,bg=1,xlim=c(0,1),ylim=c(0,1)) > > > > What I would like to end up with is a 2 dimensional matrix that > > indicates presence/absence of grass in any given pixel as per the > > image generated from the above graphics plot. > > Instead of drawing to the screen, you can use the 'png' function to > create a graphics device that "draws" to an image file. Then you can > read that image file into R and get it as a matrix. > > You probably also want to set some of the margin and axis parameters > so the plotting region fills the whole device, and you dont have the > axes and tick marks etc confusing the matrix. > > That's some pointers for starters. I've not had breakfast yet... > > Barry > > > ********************************DISCLAIMER**************************** > The information contained in the above e-mail message or messages > (which includes any attachments) is confidential and may be legally > privileged. It is intended only for the use of the person or entity > to which it is addressed. If you are not the addressee any form of > disclosure, copying, modification, distribution or any action taken > or omitted in reliance on the information is unauthorised. Opinions > contained in the message(s) do not necessarily reflect the opinions > of the Queensland Government and its authorities. If you received > this communication in error, please notify the sender immediately > and delete it from your computer system network. > > > ______________________________________________ > 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. ______________________________________________ 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.