library(sf)

## Linking to GEOS 3.12.2, GDAL 3.9.3, PROJ 9.4.1; sf_use_s2() is TRUE

library(rnaturalearth)
par(mar = c(2,2,0,0) + .1)
ne = ne_countries() |> st_geometry()
plot(ne, axes = TRUE)

ne |> st_transform("+proj=eqc") |> plot(axes = TRUE)

ne |> st_transform("+proj=eck4") |> plot(axes = TRUE)

ne |> st_transform("+proj=ortho") |> plot(axes = TRUE)

ne |> st_transform("+proj=ortho +lon_0=180") |> plot(axes = TRUE)

# ne |> st_transform("+proj=merc +lon_0=0") |> plot(axes = TRUE)