Is there an easy way to create a "movie" by stitching together several plots, within R?
+1
A:
I'm not sure it is possible in R. I did a project once when data points from R were exported to a MySQL database and a Flex/Flash application picked up those data points and gave animated visualizations..
Srirangan
2009-08-19 06:40:37
You don't need a database. In a loop, save all your images. Then use a command-line tool to stitch them together; imagemagick is one possibility.
Dirk Eddelbuettel
2009-08-19 12:14:50
Yes, this was the easiest way. I guess due to OS modularity, it really isn't possible to do this within R unless R is compiled with a special library or such.
Ryan Rosario
2009-08-19 15:07:51
This is a clever technique, Srirangan. I learned many years ago that when someone says 'it's not possible', they mean 'I don't know how to do it'. The clever part of the technique is that in a forum such as SO, someone is bound to tell you how to do it. I'm not being sarcastic, by the way. I REALLY think it's a good technique, and I'm going to try it out. Thanks Srirangan.
pavium
2009-08-20 00:09:23
Sure. But it is still essentially the same thing that I said. R can't do it and you are depending on an external application to do so. I citied the case where I had used Flex/ActionScript, Ryan recommended the the use of ImageMagick but in the end you are dependent on an external app. That was my point. I was nowhere claiming that my way was the only way to do it. ;)
Srirangan
2009-08-20 03:14:59
+2
A:
If you wrap your R script within a larger Perl/Python/etc. script, you can stitch graphs together with your favorite command-line image stitching tool.
To run your R script with a wrapper script, use the R CMD BATCH method.
Alex Reynolds
2009-08-19 06:47:02
Well where does require a Perl/Python script? Also, look at Rscript (and littler) as better alternatives to 'R CMD BATCH'.
Dirk Eddelbuettel
2009-08-19 12:12:47
You don't need another language. You can use a shell like bash. Whatever you want. There are lots of options. I use R CMD BATCH because it is more or less universal across platforms.
Alex Reynolds
2009-08-19 14:14:44
I found that it is pretty easy once ImageMagick and ffmpeg are installed.
Ryan Rosario
2009-08-19 15:04:55
+10
A:
Here is one method I found using R help:
To create the individual image frames:
for (i in 1:5) {
jpeg("/tmp/foo%02d.jpg")
my.plot(i)
}
dev.off()
To make the movie (which calls "convert", part of ImageMagick I suppose):
make.mov <- function(){
unlink("plot.mpg")
system("convert -delay 0.5 plot*.jpg plot.mpg")
}
May require a bit of tinkering, but this seemed pretty simple once everything was installed.
Of course, anywhere you see "jpg" or "jpeg", you can substitute GIF or PNG to suit your fancy.
Ryan Rosario
2009-08-19 15:07:02
You can even keep jpeg() and dev.off() outside the loop -- if you use an appropriate filename as e.g. jpeg("/tmp/foo%02d.png"), R will simply create new files during your loop. No need for you to compute the filename. Makes it even easier.
Dirk Eddelbuettel
2009-08-19 15:36:41
You should make Dirk's fix and then accept your own answer. Good solution.
JD Long
2009-08-19 15:47:10
+2
A:
I think you can do this also with the write.gif function in the caTools library. You'd have to get your graph into a multi-frame image first. I'm not sure how to do that. Anyone? Bueller?
The classic example of an animated GIF is this code which I didn't write but I did blog about some time ago:
library(fields) # for tim.colors
library(caTools) # for write.gif
m = 400 # grid size
C = complex( real=rep(seq(-1.8,0.6, length.out=m), each=m ), imag=rep(seq(-1.2,1.2, length.out=m), m ) )
C = matrix(C,m,m)
Z = 0
X = array(0, c(m,m,20))
for (k in 1:20) {
Z = Z^2+C
X[,,k] = exp(-abs(Z))
}
image(X[,,k], col=tim.colors(256)) # show final image in R
write.gif(X, “Mandelbrot.gif”, col=tim.colors(256), delay=100)
Code credit goes to Jarek Tuszynski, PhD.
JD Long
2009-08-19 15:44:34
+3
A:
Here's an example of using Flash to animate graphics created in R: Animate R Graphics with Flash.
David Smith
2009-08-19 17:22:07
A:
I've done some movies using XNview's (open source graphics viewer) Create Slideshow function. I wanted to show trends through time with spatial data, so I just created a series of plots, named sequentially [paste() is your friend for all sorts of naming calistethics] then loaded them into XNviews slideshow dialogue and set a few timer variables, voila. Took like 5 minutes to learn how to do it and produce some executable graphics.
kpierce8
2009-08-21 03:56:57