Re: [R] basic question about changing limits on generated plots
On Wed, Feb 23, 2005 at 09:14:50PM -0500, rif wrote:
This does not do what the matlab code I posted does (the matlab code
also works in the free program octave, if you want to try). The
matlab code moves already plotted data within the window (replots it).
When I first type plot(1:10,1:10), I see a graph with axis limits [1
10 1 10]. When I type hold on (to keep my original data), and execute
plot(2:12,5:15), the plot I see is equivalent to the plot I'd have
gotten if I'd originally specified axis limits [1 12 5 15]. By
contrast, in the R code you sent, it's as if I'm superimposing two
unrelated plots.
Essentially, the underlying task is that I want to compare multiple
functions, but I do not know good limits for the complete set of
functions when I start. Being able to adjust the graph to show all
the data I've plotted so far would be extremely useful for exploratory
analysis. This is the mode I and colleagues generally use matlab and
octave in.
Does this question get asked all the time? It seems to be something
that would come up a lot for people who switch from Matlab/Octave to
R, but I searched the archives and didn't really see anything.
FWIW, I use constructs such as
plotfuncs - function(x, func, ...)
{
y - as.list(1:length(func));
for (i in 1:length(func))
{
y[[i]] - sapply(x, func[[i]]);
}
xlim - c(min(x), max(x));
ylim - c(min(sapply(y, min)), max(sapply(y, max)));
plot.new();
plot.window(xlim, ylim, ...);
for (i in 1:length(func))
{
lines(x, y[[i]]);
}
axis(1, ...);
axis(2, ...);
box(...);
}
plotfuncs(1:100 / 100, list(sqrt, log, exp))
which allows you to add further functions incrementally, as in
plotfuncs(1:100 / 100, list(sqrt, log, exp, function(x) {3 / (x + 1)}))
Perhaps, that's what you have in mind, and probably, that's what (some)
others do...
Best regards, Jan
--
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Re: [R] basic question about changing limits on generated plots
On Wed, 2005-02-23 at 17:42 -0500, rif wrote: Is it possible to change the limits on plots that are already on the screen? In particular, is there any R equivalent to the sequence of matlab commands plot(1:10,1:10) hold on plot(2:12,5:15) I know I can use points and lines to add points and lines to plots, but the limits of the plot do not change when I do this. Looking at various examples, it seems that the answer is no, but I wanted to make sure. This seems to make exploratory data analysis somewhat more challenging. It also seems like it would be plausible to write a package on top of the standard graphics functions that keeps track of what you've done and automatically replots. Which makes me think, has someone already done this? Cheers, rif I have not used Matlab, but I suspect that you want to use: par(new = TRUE) For example: plot(1:10,1:10) # Check plot region limits par(usr) [1] 0.64 10.36 0.64 10.36 # Set par(new) to not overwrite existing plot par(new = TRUE) plot(2:12,5:15) # Re-check plot region limits par(usr) [1] 1.6 12.4 4.6 15.4 See ?par for more information. Note also that par(usr) is not read-only, so you can explicitly change it when required: plot(1:10,1:10) par(usr) [1] 0.64 10.36 0.64 10.36 # Now reset the plot region limits par(usr = c(0, 20, 0, 20)) # Check it par(usr) [1] 0 20 0 20 You do not indicate what OS you are using, but Under Windows, there is an ability to record plots. See R Windows FAQ 4.2. Otherwise, save the R code that you use to generate the plot and either CP it or source() it or use ESS. 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
Re: [R] basic question about changing limits on generated plots
On Wed, 2005-02-23 at 17:42 -0500, rif wrote: Is it possible to change the limits on plots that are already on the screen? In particular, is there any R equivalent to the sequence of matlab commands plot(1:10,1:10) hold on plot(2:12,5:15) rif I have not used Matlab, but I suspect that you want to use: par(new = TRUE) For example: plot(1:10,1:10) # Check plot region limits par(usr) [1] 0.64 10.36 0.64 10.36 # Set par(new) to not overwrite existing plot par(new = TRUE) plot(2:12,5:15) Marc Schwartz Marc, This does not do what the matlab code I posted does (the matlab code also works in the free program octave, if you want to try). The matlab code moves already plotted data within the window (replots it). When I first type plot(1:10,1:10), I see a graph with axis limits [1 10 1 10]. When I type hold on (to keep my original data), and execute plot(2:12,5:15), the plot I see is equivalent to the plot I'd have gotten if I'd originally specified axis limits [1 12 5 15]. By contrast, in the R code you sent, it's as if I'm superimposing two unrelated plots. Essentially, the underlying task is that I want to compare multiple functions, but I do not know good limits for the complete set of functions when I start. Being able to adjust the graph to show all the data I've plotted so far would be extremely useful for exploratory analysis. This is the mode I and colleagues generally use matlab and octave in. Does this question get asked all the time? It seems to be something that would come up a lot for people who switch from Matlab/Octave to R, but I searched the archives and didn't really see anything. Cheers, rif __ 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
Re: [R] basic question about changing limits on generated plots
On Wed, 2005-02-23 at 21:14 -0500, rif wrote: snip Marc, This does not do what the matlab code I posted does (the matlab code also works in the free program octave, if you want to try). The matlab code moves already plotted data within the window (replots it). When I first type plot(1:10,1:10), I see a graph with axis limits [1 10 1 10]. When I type hold on (to keep my original data), and execute plot(2:12,5:15), the plot I see is equivalent to the plot I'd have gotten if I'd originally specified axis limits [1 12 5 15]. By contrast, in the R code you sent, it's as if I'm superimposing two unrelated plots. Essentially, the underlying task is that I want to compare multiple functions, but I do not know good limits for the complete set of functions when I start. Being able to adjust the graph to show all the data I've plotted so far would be extremely useful for exploratory analysis. This is the mode I and colleagues generally use matlab and octave in. Does this question get asked all the time? It seems to be something that would come up a lot for people who switch from Matlab/Octave to R, but I searched the archives and didn't really see anything. Cheers, rif A general statement: There are members of the R Community engaged in Octave, so there is some overlap, at least in terms of expertise with both tools. Perhaps they can offer some insight here. The good news is that I have Octave installed on my FC3 system, so I was able to get a feel for what you are referring to. A search of the R archives would suggest that there is not a direct parallel in terms of adding a new set of data to an existing plot, while having the entire coordinate system adjusted to the new data in a single step. There are references to what I suggested, the use of the 'add' argument in some plot functions and of course the use of points() and lines(). I would defer to others with more low-level knowledge of the standard R screen based plotting devices, but from my past review of code (both R and C) and reasonable knowledge, I am not sure that this can be done without some form of two step approach involving re-plotting the original data using an updated coordinate system based upon the new data and then overlaying the new data. Presumably at a low level, this is what Octave and Matlab do, since I noted that the plot device seems to be completely re-drawn upon the second plot call. Since Octave is open source, one can of course review the code to see what is truly happening. The key it seems would be to transparently save the original data as an object, re-plot it with the adjusted coordinate system and then add the new data. I would guess that with some thought, one could create some wrapper plotting functions or methods that would save the data object(s) in a plot environment so that each successive plot call layers the older data sets in turn and then add the newest data set. All this done in a coordinate system that is re-configured each time, based upon the maximum x and y axis ranges required for the multiple datasets that have been plotted to that point. Almost sounds like a plot stack, to use an assembly language metaphor. You might also want to look at the xgobi package on CRAN, which provides an interface to the XGobi system: http://www.research.att.com/areas/stat/xgobi/ or the ggobi system: http://www.ggobi.org/ which is accessible from R. These are both dynamic data visualization tools. HTH, Marc __ 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
