Issue with SpatVector wrapping when plotting

Question

When plotting a SpatVector using ggplot2, if I define a projection using coord_sf(), it adds these lines that I think come from the data wrapping around the plot extent. Best way to fix?

library(ggplot2)
library(tidyterra)
library(terra)
library(rnaturalearth)

coast <- rnaturalearth::ne_coastline(returnclass = "sv")

ggplot() +
  geom_spatvector(data = coast) +
  theme_minimal()

ggplot() +
  geom_spatvector(data = coast) +
  coord_sf(crs = "+proj=robin",) +  # Robinson projection
  theme_minimal()

Leaving the similar github post here github.com/r-spatial/sf/issues/1372#issuecomment-614726688 - they say that the medium and large version of ne_coastline don't have the problem. — lailaps
– lailaps, Commented Nov 7 at 10:25

L Tyrone · Accepted Answer · 2025-11-06 18:59:42Z

5

Use the terra::normalize.longitude() function to correct this:

library(ggplot2)
library(tidyterra)
library(terra)
library(rnaturalearth)

coast <- ne_coastline(returnclass = "sv")
coast <- normalize.longitude(coast)

ggplot() +
  geom_spatvector(data = coast) +
  coord_sf(crs = "+proj=robin") +
  theme_minimal()

answered Nov 6 at 18:59

L Tyrone

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L Tyrone Nov 7 at 0:55

For anyone wanting to dig a little deeper into where/why this occurs for this dataset, coast <- rnaturalearth::ne_coastline() |> dplyr::slice(94) terminates at 180 lon 68.96365 lat, and that point is the source of the error.

Robert Hijmans · Accepted Answer · 2025-11-07 06:08:48Z

5

Another work-around is to crop the input data such that are no points at -180 or 180 degrees longitude

library(terra)
coast <- rnaturalearth::ne_coastline(returnclass = "sv")

x <- crop(coast, as.polygons(ext(-180,180,-90,90) - .001))
r <- project(x, "+proj=robin")
plot(r)

answered Nov 7 at 6:08

Robert Hijmans

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