Question

Is it possible to insert a raster image or a pdf image underneath a geom_line() on a ggplot2 plot?

I wanted to be quickly able to plot data over a previously calculated plot that takes a long time to generate as it uses a large amount of data.

I read through this example. However, as it is over one year old I thought there might be a different way of doing this now.

Answer 1

try ?annotation_custom in ggplot2

example,

library(png)
library(grid)
img <- readPNG(system.file("img", "Rlogo.png", package="png"))
g <- rasterGrob(img, interpolate=TRUE)

qplot(1:10, 1:10, geom="blank") +
  annotation_custom(g, xmin=-Inf, xmax=Inf, ymin=-Inf, ymax=Inf) +
  geom_point()