cartography : display a background map

[David5]

Hello,

I have a dataset containing georeferenced points. I can display these points but I would like to integrate a background map (satellite, basic background).

Here is an example of a dataset and the code to display these points:

library(sf)
library(ggplot2)

df <- data.frame(lon = c(7.389801812, 7.382449389, 7.384940219, 7.387570357, 7.37491467, 7.37739296, 7.379973102, 7.372087193, 7.382560379, 7.385341144, 7.387903333),
                 lat = c(48.42369, 48.42901459, 48.4289978, 48.42880688, 48.43111324, 48.43098717, 48.43107758,  48.43283577, 48.43077007, 48.43071995, 48.43046265),
                 mean = c(2, 5, 8, 4, 3, 5, 7, 9, 2, 10, 9)
)   

df1 <- st_as_sf(df, coords = c("lon", "lat"), crs = st_crs(df))

ggplot(df1) +
  geom_sf() +
  geom_point(
    aes(colour = mean, size = mean, geometry = geometry),
    stat = "sf_coordinates"
  )

The "get_map" or "leaflet" function could perhaps allow to display a background map (satellite, basic background) but I don't see how to integrate the function in my script, I'm a beginner in the field of cartography on R.

If you have ideas to display background maps behind my georeferenced points I'm interested!

Thank you,
David

[jlacko]

You may consider the {ggmap} approach shown in this older post: Best packages for making map? leaflet vs ggmap vs sf vs ...? - #2 by jlacko

Satellite might be more complex, but regular terrain or toner from Stamen are often good enough options.

[David5]

Thanks, ggmap and ggplot work well together. The background maps: "terrain", "terrain-background" are not bad.

But do you know a way to get an "Open Street Map" type background with ggmap? Without having to enter an API Key.

Thank you,
David

[jlacko]

For Open Street Map background tiles you will want to look into ggmap::get_openstreetmap() documentation.