I have to create a bunch of graphs with a lot of data points. So far, I've been doing this by plotting all of them into one pdf
-file:
pdf("testgraph.pdf")
par(mfrow=c(3,3))
for (i in 2:length(names(mtcars))){
plot(mtcars[,1], mtcars[,i])
}
dev.off()
However, with a lot of data points the pdf
file becomes too large. As I'm not interested in outstanding quality, I don't care if my plots are vector graphics or not. So I thought of creating the plots as png
and subsequently inserting them into a pdf
file. Is there a way to do this except of creating R
graphs and inserting them into pdf
with knitr
(which I think is too tedious for such a simple job)?
You can
png
package to read those back in andgrid.arrange
library(png)
library(grid)
library(gridExtra)
thePlots <- lapply (2:length(names(mtcars)), function(i) {
png("testgraph.png")
plot(mtcars[,1], mtcars[,i])
dev.off()
rasterGrob(readPNG("testgraph.png", native = FALSE),
interpolate = FALSE)
})
pdf("testgraph.pdf")
do.call(grid.arrange, c(thePlots, ncol = 3))
dev.off()