How to create a map with transparent background?

Question

I'm trying to create and save a map with transparent background instead of a white (or any other color) one using the R package tmap.

Apart from what's in the example below, I tried using bg.color = "transparent", bg.color = NA, and bg.color = NULL in both tmap_options and tm_layout.

Version info:

• tmap: 2.2
• tmaptools: 2.0-1

library(tmap)
data("World")

tmap_options (bg.color = "#00000000", basemaps.alpha = 0)
map <- tm_shape(World) +
  tm_polygons("HPI") +
  tm_layout (frame = FALSE, bg.color = "#00000000")

tmap_save (map, filename = "~/test.png")

Am I doing something wrong or is this simply a limitation of the package? Thanks a lot!

Answer 1

I found a trick!

I was looking for the same feature to draw a stack of maps in InDesign with outputs from R, tmap and I needed the background to be transparent.

Here my solution, given your code:

library(tmap)
data("World")

par(bg=NA)
map <- tm_shape(World) +
  tm_polygons("HPI") +
  tm_layout (frame = FALSE, bg.color = "transparent")

tmap_save (map, filename = "~/test.eps", bg="transparent") # Note the eps extension

Caveat: testing this with different output formats, I realized that it doesn't work with png or jpg.