Inserting an image to a log chart ggplot2

Question

Is it possible in R (ggplot2) to add an image to a chart with log y-axis. I mean:

ggplot(mtcars, aes(x=mpg, y=disp))+
geom_line()+
coord_trans(y="log2")

If Yes - How?

For example it doesn't work:

image <- readPNG('/myFolder/car.png')

ggplot(mtcars, aes(x=mpg, y=disp))+
geom_line()+
coord_trans(y="log2")+
annotation_raster(image, ymin = 100, ymax= 200, xmin = 15, xmax = 
20,interpolate = FALSE)

Error: annotation_raster only works with Cartesian coordinates

not sure what you mean by _"an image to a chart with log y-axis"_ — acylam, Jun 18 '18 at 16:04
What do you mean by "it doesn't work"? Does it give you an error? or no error, but doesn't give you what you want? — acylam, Jun 18 '18 at 16:17
@useR, Yes. it give "Error: annotation_raster only works with Cartesian coordinates". — MariaMaria1, Jun 18 '18 at 16:19
Is this question what you are looking for: [inserting an image to ggplot2](https://stackoverflow.com/questions/9917049/inserting-an-image-to-ggplot2) — steveb, Jun 18 '18 at 16:20

score 0 · Accepted Answer · answered Jun 20 '18 at 16:44

0

library(ggplot2)
library(magick)
library(grid)

image <- image_read('/myFolder/car.png')

ggplot(mtcars, aes(x=mpg, y=disp))+
geom_line()+
coord_trans(y="log2")

// add image
grid.raster(image, unit(0.95, "npc"), y = unit(0.95, "npc"))

answered Jun 20 '18 at 16:44

MariaMaria1

25
1
6

score 0 · Answer 2 · answered Jun 20 '18 at 19:10

Try this,

library(egg)

image <- readPNG(system.file("img", "Rlogo.png", package="png"))

dummy <- data.frame(x=15,y=100, data=I(list(image)))
ggplot(mtcars, aes(x=mpg, y=disp))+
  geom_line()+
  coord_trans(y="log2")+
  geom_custom(data=dummy, aes(x,y,data=data), 
              grob_fun=rasterGrob,
              fun_params = list(height=unit(1,"cm")))

enter image description here

Inserting an image to a log chart ggplot2

2 Answers2