plot fails to render with specific lon_0 value in coord_sf crs string (works with lon_0=27.1, fails with lon_0=27.0)

[misea]

I found a problem with rendering a world map with a very specific rotation (I was just trying to animate a rotating globe)
I expected any valid integer value of lon0 in my crs string of this form to work:

coord_sf(crs = "+proj=ortho +lat_0=0 +lon_0=27") 

but it fails with that specific string, while succeeding with other similar values

library(ggplot2)
library(rnaturalearth)
library(sf)
#> Linking to GEOS 3.11.0, GDAL 3.5.3, PROJ 9.1.0; sf_use_s2() is TRUE

world <- ne_countries(scale = "medium", returnclass = "sf")


world_plot <- ggplot(data = world) +
   geom_sf(fill = "lightblue", color = "gray") +
     theme_void()

# This works
world_plot + coord_sf(crs = "+proj=ortho +lat_0=0 +lon_0=26.9") 

# So does this
world_plot + coord_sf(crs = "+proj=ortho +lat_0=0 +lon_0=27.1") 

  
# But this fails with "Error in `grid.Call.graphics"
world_plot + coord_sf(crs = "+proj=ortho +lat_0=0 +lon_0=27.0") 
#> Error in grid.Call.graphics(C_path, x$x, x$y, index, switch(x$rule, winding = 1L, : Invalid graphics path

^{Created on 2024-11-10 with reprex v2.1.1}

[teunbrand]

Thanks for the report! It seems like the problem can be reproduced outside ggplot2, which tells me the source of the error comes from elsewhere.

library(ggplot2)
library(rnaturalearth)
library(sf)
#> Linking to GEOS 3.12.1, GDAL 3.8.4, PROJ 9.3.1; sf_use_s2() is TRUE

world <- ne_countries(scale = "medium", returnclass = "sf") |>
  st_as_sfc() |>
  st_transform(crs = st_crs("+proj=ortho +lat_0=0 +lon_0=27.0")) |>
  plot()

#> Error in polypath(p_bind(L), border = border[i], lty = lty[i], lwd = lwd[i], : Invalid graphics path

^{Created on 2024-11-11 with reprex v2.1.1}

I'd try posting this as an issue in {sf} instead.

[misea]

OK - now reported here: r-spatial/sf#2477

[teunbrand]

Alright, good. If it appears that the issue originates from ggplot2 anyway we can reopen this issue.