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I plot a simple linear regression using R.
I would like to save that image as PNG or JPEG, is it possible to do it automatically? (via code)
There are two different questions: First, I am already looking at the plot on my monitor and I would like to save it as is. Second, I have not yet generated the plot, but I would like to directly save it to disk when I execute my plotting code.
There are two closely-related questions, and an answer for each.
1. An image will be generated in future in my script, how do I save it to disk?
To save a plot, you need to do the following:
Open a device, using png(), bmp(), pdf() or similar
Plot your model
Close the device using dev.off()
Some example code for saving the plot to a png file:
fit <- lm(some ~ model)
png(filename="your/file/location/name.png")
plot(fit)
dev.off()
This is described in the (combined) help page for the graphical formats ?png, ?bmp, ?jpeg and ?tiff as well as in the separate help page for ?pdf.
Note however that the image might look different on disk to the same plot directly plotted to your screen, for example if you have resized the on-screen window.
Note that if your plot is made by either lattice or ggplot2 you have to explicitly print the plot. See this answer that explains this in more detail and also links to the R FAQ: ggplot's qplot does not execute on sourcing
2. I'm currently looking at a plot on my screen and I want to copy it 'as-is' to disk.
dev.print(pdf, 'filename.pdf')
This should copy the image perfectly, respecting any resizing you have done to the interactive window. You can, as in the first part of this answer, replace pdf with other filetypes such as png.
If you want to keep seeing the plot in R, another option is to use dev.copy:
X11 ()
plot (x,y)
dev.copy(jpeg,filename="plot.jpg");
dev.off ();
If you reach a clutter of too many plot windows in R, use graphics.off() to close all of the plot windows.
If you use ggplot2 the preferred way of saving is to use ggsave. First you have to plot, after creating the plot you call ggsave:
ggplot(...)
ggsave("plot.png")
The format of the image is determined by the extension you choose for the filename. Additional parameters can be passed to ggsave, notably width, height, and dpi.
Like this
png('filename.png')
# make plot
dev.off()
or this
# sometimes plots do better in vector graphics
svg('filename.svg')
# make plot
dev.off()
or this
pdf('filename.pdf')
# make plot
dev.off()
And probably others too. They're all listed together in the help pages.
For the first question, I find dev.print to be the best when working interactively. First, you set up your plot visually and when you are happy with what you see, you can ask R to save the current plot to disk
dev.print(pdf, file="filename.pdf");
You can replace pdf with other formats such as png.
This will copy the image exactly as you see it on screen. The problem with dev.copy is that the image is often different and doesn't remember the window size and aspect ratio - it forces the plot to be square by default.
For the second question, (as others have already answered), you must direct the output to disk before you execute your plotting commands
pdf('filename.pdf')
plot( yourdata )
points (some_more_data)
dev.off() # to complete the writing process and return output to your monitor
If you use R Studio http://rstudio.org/ there is a special menu to save you plot as any format you like and at any resolution you choose
If you open a device using png(), bmp(), pdf() etc. as suggested by Andrie (the best answer), the windows with plots will not pop up open, just *.png, *bmp or *.pdf files will be created. This is convenient in massive calculations, since R can handle only limited number of graphic windows.
However, if you want to see the plots and also have them saved, call savePlot(filename, type) after the plots are drawn and the window containing them is active.
plotpath<- file.path(path, "PLOT_name",paste("plot_",file,".png",sep=""))
png(filename=plotpath)
plot(x,y, main= file)
dev.off()
To add to these answers, if you have an R script containing calls that generate plots to screen (the native device), then these can all be saved to a pdf file (the default device for a non-interactive shell) "Rplots.pdf" (the default name) by redirecting the script into R from the terminal (assuming you are running linux or OS X), e.g.:
R < myscript.R --no-save
This could be converted to jpg/png as necessary
In some cases one wants to both save and print a base r plot. I spent a bit of time and came up with this utility function:
x = 1:10
basesave = function(expr, filename, print=T) {
#extension
exten = stringr::str_match(filename, "\\.(\\w+)$")[, 2]
switch(exten,
png = {
png(filename)
eval(expr, envir = parent.frame())
dev.off()
},
{stop("filetype not recognized")})
#print?
if (print) eval(expr, envir = parent.frame())
invisible(NULL)
}
#plots, but doesn't save
plot(x)
#saves, but doesn't plot
png("test.png")
plot(x)
dev.off()
#both
basesave(quote(plot(x)), "test.png")
#works with pipe too
quote(plot(x)) %>% basesave("test.png")
Note that one must use quote, otherwise the plot(x) call is run in the global environment and NULL gets passed to basesave().
dev.copy(png,'path/pngFile.png')
plot(YData ~ XData, data = mydata)
dev.off()
I plot a simple linear regression using R.
I would like to save that image as PNG or JPEG, is it possible to do it automatically? (via code)
There are two different questions: First, I am already looking at the plot on my monitor and I would like to save it as is. Second, I have not yet generated the plot, but I would like to directly save it to disk when I execute my plotting code.
There are two closely-related questions, and an answer for each.
1. An image will be generated in future in my script, how do I save it to disk?
To save a plot, you need to do the following:
Open a device, using png(), bmp(), pdf() or similar
Plot your model
Close the device using dev.off()
Some example code for saving the plot to a png file:
fit <- lm(some ~ model)
png(filename="your/file/location/name.png")
plot(fit)
dev.off()
This is described in the (combined) help page for the graphical formats ?png, ?bmp, ?jpeg and ?tiff as well as in the separate help page for ?pdf.
Note however that the image might look different on disk to the same plot directly plotted to your screen, for example if you have resized the on-screen window.
Note that if your plot is made by either lattice or ggplot2 you have to explicitly print the plot. See this answer that explains this in more detail and also links to the R FAQ: ggplot's qplot does not execute on sourcing
2. I'm currently looking at a plot on my screen and I want to copy it 'as-is' to disk.
dev.print(pdf, 'filename.pdf')
This should copy the image perfectly, respecting any resizing you have done to the interactive window. You can, as in the first part of this answer, replace pdf with other filetypes such as png.
If you want to keep seeing the plot in R, another option is to use dev.copy:
X11 ()
plot (x,y)
dev.copy(jpeg,filename="plot.jpg");
dev.off ();
If you reach a clutter of too many plot windows in R, use graphics.off() to close all of the plot windows.
If you use ggplot2 the preferred way of saving is to use ggsave. First you have to plot, after creating the plot you call ggsave:
ggplot(...)
ggsave("plot.png")
The format of the image is determined by the extension you choose for the filename. Additional parameters can be passed to ggsave, notably width, height, and dpi.
Like this
png('filename.png')
# make plot
dev.off()
or this
# sometimes plots do better in vector graphics
svg('filename.svg')
# make plot
dev.off()
or this
pdf('filename.pdf')
# make plot
dev.off()
And probably others too. They're all listed together in the help pages.
For the first question, I find dev.print to be the best when working interactively. First, you set up your plot visually and when you are happy with what you see, you can ask R to save the current plot to disk
dev.print(pdf, file="filename.pdf");
You can replace pdf with other formats such as png.
This will copy the image exactly as you see it on screen. The problem with dev.copy is that the image is often different and doesn't remember the window size and aspect ratio - it forces the plot to be square by default.
For the second question, (as others have already answered), you must direct the output to disk before you execute your plotting commands
pdf('filename.pdf')
plot( yourdata )
points (some_more_data)
dev.off() # to complete the writing process and return output to your monitor
If you use R Studio http://rstudio.org/ there is a special menu to save you plot as any format you like and at any resolution you choose
If you open a device using png(), bmp(), pdf() etc. as suggested by Andrie (the best answer), the windows with plots will not pop up open, just *.png, *bmp or *.pdf files will be created. This is convenient in massive calculations, since R can handle only limited number of graphic windows.
However, if you want to see the plots and also have them saved, call savePlot(filename, type) after the plots are drawn and the window containing them is active.
plotpath<- file.path(path, "PLOT_name",paste("plot_",file,".png",sep=""))
png(filename=plotpath)
plot(x,y, main= file)
dev.off()
To add to these answers, if you have an R script containing calls that generate plots to screen (the native device), then these can all be saved to a pdf file (the default device for a non-interactive shell) "Rplots.pdf" (the default name) by redirecting the script into R from the terminal (assuming you are running linux or OS X), e.g.:
R < myscript.R --no-save
This could be converted to jpg/png as necessary
In some cases one wants to both save and print a base r plot. I spent a bit of time and came up with this utility function:
x = 1:10
basesave = function(expr, filename, print=T) {
#extension
exten = stringr::str_match(filename, "\\.(\\w+)$")[, 2]
switch(exten,
png = {
png(filename)
eval(expr, envir = parent.frame())
dev.off()
},
{stop("filetype not recognized")})
#print?
if (print) eval(expr, envir = parent.frame())
invisible(NULL)
}
#plots, but doesn't save
plot(x)
#saves, but doesn't plot
png("test.png")
plot(x)
dev.off()
#both
basesave(quote(plot(x)), "test.png")
#works with pipe too
quote(plot(x)) %>% basesave("test.png")
Note that one must use quote, otherwise the plot(x) call is run in the global environment and NULL gets passed to basesave().
dev.copy(png,'path/pngFile.png')
plot(YData ~ XData, data = mydata)
dev.off()
This is my code which is part of a larger script.
for(d1 in names(survD)){
survfit1 <- survfit(Surv(time=survD[[d1]][,"time"],
event=survD[[d1]][,"death"],type='right')~1)
png(paste(survPath,"/surv_",d1,".png",sep=""))
plot(survfit1,xlab="Years",ylab="Survival probability",xmax=xmax1)
}
I don't have a good idea of what this code does yet, so I'm trying to look at each individual plot to see what it is. The problem is, whenever I run this in the R command line in the terminal in linux, nothing appears. I have to use dev.off() multiple times and then rerun this code:
plot(survfit1)
for something to appear. How can I see all the plots?
Sounds like this is really what you want:
for(d1 in names(survD)){
survfit1 <- survfit(Surv(time=survD[[d1]][,"time"],
event=survD[[d1]][,"death"],type='right')~1)
x11() ## open up new graphical window for each plot (to avoid overwriting)
plot(survfit1,xlab="Years",ylab="Survival probability",
xmax=xmax1, main = d1) ## use different titles to distinguish those plots
}
This will produce plots on normal graphical windows.
If you want to use the original code, you'd better do this way:
for(d1 in names(survD)){
survfit1 <- survfit(Surv(time=survD[[d1]][,"time"],
event=survD[[d1]][,"death"],type='right')~1)
png(paste(survPath,"/surv_",d1,".png",sep=""))
plot(survfit1,xlab="Years",ylab="Survival probability",xmax=xmax1)
dev.off()
}
Then, have a look at the directory given by getwd(). All the plots are saved in png files.
Calling Sys.sleep(.1) might help during the for loop. Maybe try:
for(d1 in names(survD)){
survfit1 <- survfit(Surv(time=survD[[d1]][,"time"],
event=survD[[d1]][,"death"],type='right')~1)
Sys.sleep(.1)
png(paste(survPath,"/surv_",d1,".png",sep="", collapse="))
plot(survfit1,xlab="Years",ylab="Survival probability",xmax=xmax1)
dev.off()
}
Is there any way in R to create a png and a pdf simultaneously without having to run the same code twice? I'd like both a raster and vector version of some figures to be produced without having to do an external conversion and without rerunning the code if possible. dev.copy2pdf sounds like what I need, but it seems that it only works from interactive devices.
Here's an example of what I'm doing:
pdf("temp.pdf")
plot(1:10)
#more drawing here
dev.off()
png("temp.png")
plot(1:10)
#more drawing here
dev.off()
Which I'd like to shorten to:
start()
plot(1:10)
#more drawing here
saveToPDF()
saveToPNG()
There is an existing function dev.copy2pdf(), which does just what it says it will. There is also a function dev.print() which looks like it would make copying to a "*.png" file easy, but is in my experience pretty hinky.
The following two functions work well and have the added advantages of being uniformly named, and of taking all of their arguments in the same order as the familiar and related pdf() and png() functions:
saveToPDF <- function(...) {
d = dev.copy(pdf,...)
dev.off(d)
}
saveToPNG <- function(...) {
d = dev.copy(png,...)
dev.off(d)
}
## Try them out
plot(rnorm(99), col="red")
saveToPDF("my.pdf", height=4,width=7)
saveToPNG("my.png", height=600, width=400)
I'm trying to save a ggplot within a function using graphics devices. But I found the code produces empty graphs. Below is a very very simple example.
library(ggplot2)
ff <- function(){
jpeg("a.jpg")
qplot(1:20, 1:20)
dev.off()
}
ff()
If I only run the content of the function, everything is fine. I know that using ggsave() will do the thing that I want, but I am just wondering why jpeg() plus dev.off() doesn't work. I tried this with different versions of R, and the problem persists.
You should use ggsave instead of the jpeg(); print(p); dev.off() sequence. ggsave is a wrapper that does exactly what you intend to do with your function, except that it offers more options and versatility. You can specify the type of output explicitly, e.g. jpg or pdf, or it will guess from your filename extension.
So your code might become something like:
p <- qplot(1:20, 1:20)
ggsave(filename="a.jpg", plot=p)
See ?ggsave for more details
The reason why the original behaviour in your code doesn't worked is indeed a frequently asked question (on stackoverlflow as well as the R FAQs on CRAN). You need to insert a print statement to print the plot. In the interactive console, the print is silently execututed in the background.
These plots have to be printed:
ff <- function(){
jpeg("a.jpg")
p <- qplot(1:20, 1:20)
print(p)
dev.off()
}
ff()
This is a very common mistake.