I made a plot in R and I want to repeat all the commands (like plot(), legend() or line()) that were carried out for this plot, with some minor changes. For example I want to set the axes to logarithmic scale and change the title of the plot.
In gnuplot I would use the replot command.
plot ...
set title "The same plot with logarithmic axes"
set logscale
replot
Is something like this possible in R. The only thing that comes to my mind of doing this (besides changing the values manually and re-run the lines of codes) would be setting up a function, that asks for all parameters that might be changed by the user.
Thanks for your help,
Sven
R uses a pen and paper graphics model - once the plot has been drawn on the device that is it. If you want to change some aspect of the plot, you need to replay the graphics function calls that produce the plot with the changes made to the code.
Depending on what you are really doing there are two options:
If this is just for you, write code in a text editor / IDE that knows R and can send chunks of code at a time to R. That way the code to produce the figure is recorded in a separate script which you can paste into/send to R making the changes you need each time to the script.
If you are going to be doing this often, then write yourself a wrapper plotting function that encapsulates the plot code you want but allows you to pass in arguments to alter the aspects you want.
Lattice and ggplot2 are a little different as they are based on grid graphics and create objects that when printed produce a plot on the device. One can manipulate that object to alter what is drawn, and with grid one can push and pop things on to / off a viewport.
Related
I would like to produce a series of plots in both high-resolution and low-resolution versions, or stated differently using two different file types (.png and .eps). I'd like to know the best/least repetetive way to do this. I am using the gplot function in sna, and the plot has a custom legend outside the plot area. I wrote a function something like this:
library(sna)
plotfun <- function(net){
png("test.png",width=800)
p <- gplot(net)
par(xpd=T)
legend(max(p[,1])+1,max(p[,2]),legend=letters[1:10],title="custom legend")
dev.off()
seteps()
postscript(test.eps)
#repeat all the plotting commands, which are much longer in real life
dev.off()
}
#try it with some random data
plotfun(rgraph(10))
This is perfectly functional but seems inefficient and clumsy. The more general version of this question is: if for any reason I want to create a plot (including extra layers like my custom legend), store it as an object, and then plot it later, is there a way to do this? Incidentally, this question didn't seem sna specific to me at first, but in trying to reproduce the problem using a similar function with plot, I couldn't get the legend to appear correctly, so this solution to the outside-the-plot-area legend doesn't seem general.
I would recommend generate graphs only in Postscript/PDF from R and then generate bitmaps (e.g. PNG) from the Postscript/PDF using e.g. ImageMagick with -density parameter (http://www.imagemagick.org/script/command-line-options.php#density) set appropriately to get desired resolution. For example
convert -density 100 -quality 100 picture.pdf picture.png
assuming picture.pdf is 7in-by-7in (R defaults) will give you a 700x700 png picture.
With this approach you will not have to worry that the picture comes out formatted differently depending which R device (pdf() vs png()) is used.
I have some problems of using gnuplot. I just begin with it.
(1)What is the command for keeping the previous plot when I plot new data? Do I have to plot the old data and the new data at the same time?
(2)What is the command for open a new window while keep the old ones? Do I have to set the window's id by using, e.g.,
set terminal wxt 3
, before each plot?
Can anyone give me some help or some good references?
Usually, to plot several data set you would use
plot 'data1.dat', 'data2.dat'
You could also use replot to add one of the data sets later
plot 'data1.dat'
...
replot 'data2.dat'
To open a new window, you must use the window's id like with set terminal wxt 2. The old windows stay open, but you cannot interact with them anymore (zooming, scrolling etc.). See also the discussion to the quesiton Two interactive windows in Gnuplot with wxt terminal.
You already wrote the answers of your questions.
1.: You can use the replot command:
plot sin(x)
replot cos(x)
but this just expands to
plot sin(x), cos(x)
So, it replots all data and does not just add the cos(x).
2.: Yes, you can also switch between the windows to update the plots. But note that settings like ranges and labels are not stored per window / plot, but globally. If they are different for different plots, you have to change them every time.
You may also have a look at "set multiplot" to put several plots on one window / picture. But it is not so nice for interactive plotting, as you will notice.
Also, output terminals supporting multiple pages like pdfcairo will add a new page for each plot.
One interesting feature of RStudio is it allows to save multiple plots generated from a script. This however opens up the problem of how to edit multiple plots. My issue at the moment is adding lines to histograms using the abline() function. This function was designed however to work with the last plot generated by the environment. One way of course would be ad the lines as soon as the plot is generated, however I have to calculate the coordinates at the end of the algorithm, by then I have transformed the data and generated multiple plots from it. So I was wondering if there isn't a way to tell R to search for a given plot and add the line to it. I read abline() documentation but found nothing regarding it. One can always save the data necessary to generate the plot and generate it at the end of the script, but I was wondering if there isn't a less consuming memory method.
One way to get around this issue is:
1.Save your graphics as variables, for ex: hist_1=hist(x, plot=FALSE)
2.Write any code u like, for ex: very complicated code give y as a number for output
3.plot(hist_1)
4.abline(hist_1, v=y)
gives a general idea of how to edit multiple plots without having to save multiple copies of datasets and without overloading Rstudio interface. Works well with the R ubuntu terminal too.
I try to receive the data from a sensor from time to time and plot it in real time. That means the length of the dataset is not know before hand. And need to adjust the range of the graph dynamically.
I tried the following
plot(1,10, xlim=range(0,10), ylim=range(0,10), type='n')
points(1,data[1])
points(2,data[2])
But once the number of dots is beyond the range of x axis (10 in this case), the data points are out of the range. How to adjust the range accordingly?
Just issue a new plot command with an expanded range. On modern computers the time taken to recreate the plot is small and you generally will not see a delay. Any other approach will essentially do the same thing, clear the current plot and create a new plot.
The ggplot2 and lattice packages have ways of constructing a plot and updating the plot, but when the updated plot is shown it is redrawn from scratch.
There is a zoomplot function in the TeachingDemos package which will allow you to change the range of a plot, but it also will just redraw the plot from scratch (and due to changes in R 3.0.0 it is not currently working, so if you wanted to use it you would need to go back to R 2.15 or before, or wait for it to be fixed).
You can't adjust the range dynamically (sometimes Excel is better). However, you can keep track of what you've plotted, and redo the plot when you've reached the limit. You could also just make a new plot every time you get more data, which would be a way of faking a dynamic update.
How I can remove the legend in a plot in R? I tried legend<-FALSE, doesn't work.
Also, is there a better way to set the position of the legend? For example, is there
a way I can pick the location with my cursor? And I am not talking about ggplot or any fancy add-ons, just regular R plotting.
In order:
This is related to what people tried to explain to you yesterday: Think of a script as primary means of creating your R session. In ESS, you get the script as a by-product; in RStudio you can also work with commands first and then pass those to your session. Lastly, no you can't remove a legend which has already been added to a plot, but you can hopefully re-create your graph using the saved commands.
Yes, since Duncan Murdoch added support for 'topleft' etc you can use logical commands:
plot(1:10) # simple plot
legend("bottomright", "foo") # 'foo' in bottom-right corner
Yes, if you use the output of locator() as input for the legend() command.
You need to specify which plotting function is producing the legend. (Most plotting function do not plot legends by default.)
There is a locator function.