Justin, Try something like this:
par(mfrow = c(2, 1)) drawGffPlots2(data1, data2, trackingDye = TRUE, slice = "chr13", newDev = 0) plot(densities_subset$V4, densities_subset$V6, type = "h", xlim = par("usr")[1:2], xaxs = "i", xlab = "Position", ylab = "Gene Density") Using 'xaxs = "i"' in the second call to plot() should fix the x axis range at the exact values passed for 'xlim'. HTH, Marc On May 14, 2010, at 11:09 AM, Justin Fincher wrote: > Thank you for your reply, but I have additional questions. I agree that > getting the common ranges before plotting would be the best scenario, it is > just complicated by the fact that the first plot is generated with a function > where all the data is passed in and within the function the data is subset > and plotted so I don't have control over the parameters of the plot. That is > why I am trying to just make the second plot (the one I have complete control > over) match up. I tried the par("usr") but am having an odd result. Below > is from my R console. > > > par(mfrow=c(2,1)) > > drawGffPlots2(data1,data2,trackingDye=TRUE,slice="chr13",newDev=0) > NULL > > par("usr")[1] > [1] 14215173 > > plot(densities_subset$V4,densities_subset$V6,type="h",xlim=c(par("usr")[1],par("usr")[2]),xlab="Position",ylab="Gene > > Density") > > par("usr")[1] > [1] 10062761 > > This creates two rows, runs the function which populates the first row, then > I check the parameter you suggested so that I may use it for the second plot. > I then pass it to plot(), but the axes still don't line up so I check the > same parameter after the second plot has been drawn and it is very different. > Should par("usr")[1] not be exactly the same the second time I display it as > I passed it as the minimum for the second plot? Any help would be > appreciated. > > - Fincher > > > On Fri, May 14, 2010 at 11:45, Marc Schwartz <marc_schwa...@me.com> wrote: > On May 14, 2010, at 9:59 AM, Justin Fincher wrote: > > > I have two datasets that I would like to plot in a single figure. The first > > plot is generated by a function that then takes a subset of the data. (It > > is biological data so it is usually by chromosome e.g. > > function(data1,subset="chr8") ) Since not only are the chromosomes different > > sizes, but across different datasets there may be different numbers of > > points for a single chromosome, I do not know the coordinates on the x-axis > > prior to running the function. > > > > I want the scale of the second plot to align to that of the first, but I > > don't know how to find the default xlim for the graph generated by the > > function. Is there any way to access this information so I can then pass it > > to the plot() of the second plot? Thanks! > > > > - Fincher > > > The result of par("usr") will give you the actual limits of the x and y axes > (plot region) once the first graphic is drawn to the device. See ?par for > more information. Note that by default, R will extend the data ranges by 4% > (see 'xaxs' in ?par). > > However, you are better off getting the common ?range of the relevant values > in both subsets of data before plotting and then explicitly set the same x > and y axis ranges in each plot by using the 'xlim' and 'ylim' arguments to > plot(). > > HTH, > > Marc Schwartz > > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner, and is > believed to be clean. > > ______________________________________________ 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.