If you specifically need the plot to have a dimension measured in pixels, then you need to use a bitmapped format such as png and specify the output to be the size you require:
png("test.png", width = 300, height = 300, ...) DoYourPlotHere() dev.off() Do this directly using the png() device, rather than trying to convert the image format, which almost always introduces "noise". Since you are using a bitmapped format, you will experience the tradeoff with respect to the image quality (ie. pixelated) as compared to a vector based format such as PDF or PS. I would re-verify the requirements for the journal to which you are submitting the article relative to what they need for image specs. It seems unusual for a journal to request an image in this fashion, unless it is a photograph where a jpg format may be preferred or perhaps for online publication on a web page. HTH, Marc Schwartz On Tue, 2005-10-25 at 08:57 +0200, Dr. med. Peter Robinson wrote: > Thanks Marc and Jim for the tips. The PDF file that I create with R looks > about the same as the one you created. However, I need to get the graphic > to be a certain size (300 pixels wide). I have been using the ImageMagick > program to do so for other graphics: > > convert test.pdf -resize 300x300 out.pdf > > then out.pdf looks rather poor (pixelly). The original image is too big. > ANy ideas? > Thanks a lot,Peter > > > Am Mo, 24.10.2005, 22:53, schrieb Marc Schwartz (via MN): > > On Mon, 2005-10-24 at 22:32 +0200, Dr. med. Peter Robinson wrote: > > > >> Dear List, > >> > >> > >> I am sorry if this perhaps a too basic question, but I have not found > >> an answer in Google or in the R help system. I am trying to use R to do > >> a very simple analysis of some data (RT-PCR and Western analysis) with a > >> T-test and > >> to plot the results as a histogram with error bars. (I have pasted an > >> example script at the bottom of this mail). In order to use this for > >> publication, I would like to adjust the resolution and size of the final > >> image. However, even using file types such as postscript or pdf that are > >> vector based, I get rather bad-looking results with > >>> pdf(file="test.pdf") source("script at bottom of mail") dev.off() > >> > >> using either pdf or postscript or jpg devices. > >> > >> > >> Therefore I would like to ask the list, how to best produce a graphic > >> from the script below that would fit into one column of a published > >> article and have a high resolution (as eps, or failing that tiff or > >> png)? Thanks in advance for any advice, > >> > >> > >> Peter > >> > > > > <Snip of code> > > > > > > What OS are you on? > > > > > > Running your example on FC4, I get the attached output for a pdf(). > > > > > > I suspect that on your OS, the height and width arguments are not > > appropriate by default. > > > > Thus, you may need to adjust your pdf (or postscript) function call to > > explicitly specify larger height and width arguments. > > > > Also note that to generate an EPS file, pay attention to the details > > section of ?postscript, taking note of the 'onefile', 'horizontal' and > > 'paper' arguments and settings. > > > > > > Also, check with your journal to see if they specify dimensions for such > > graphics so that you can abide by their specs if provided. If they are > > using LaTeX, there are means of specifying and/or adjusting the height > > and/or width specs in the code based upon proportions of various measures > > (ie. \includegraphics[width=0.9\textwidth]{GraphicsFile.eps} ). > > > > > > HTH, > > > > > > Marc Schwartz > > > > > > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html