The point geom is used to create scatterplots, and doesn’t quite seem to be designed to do what you need, ie, display custom images. However, a similar question was answered here, which indicates that the problem can be solved in the following steps:
(1) Read the custom images you want to display,
(2) Render raster objects at the given location, size, and orientation using the rasterGrob()
function,
(3) Use a plotting function such as qplot()
,
(4) Use a geom such as annotation_custom()
for use as static annotations specifying the crude adjustments for x and y limits as mentioned by user20650.
Using the code below, I could get two custom images img1.png and img2.png positioned at the given xmin, xmax, ymin, and ymax.
library(png)
library(ggplot2)
library(gridGraphics)
setwd("c:/MyFolder/")
img1 <- readPNG("img1.png")
img2 <- readPNG("img2.png")
g1 <- rasterGrob(img1, interpolate=FALSE)
g2 <- rasterGrob(img2, interpolate=FALSE)
qplot(1:10, 1:10, geom="blank") +
annotation_custom(g1, xmin=1, xmax=3, ymin=1, ymax=3) +
annotation_custom(g2, xmin=7, xmax=9, ymin=7, ymax=9) +
geom_point()