Sf: geom_sf alpha not working for linestring

[sebdalgarno]

I expected alpha to work for linestring sf object as in geom_line. Here is a simple example:

library(ggplot2)
library(sf)

l <- st_linestring(rbind(c(2,2), c(3,3), c(3,2)))
lsf <- st_sf(geometry = st_sfc(l, crs = 4326))

ggplot(data = lsf) + geom_sf(data = lsf, lwd = 2)
ggplot(data = lsf) + geom_sf(data = lsf, alpha = 0.5, lwd = 2)

both plots above are identical.

If I try with polygon, fill transparency changes but outline remains the same.
p <- st_polygon(list(rbind(c(2,2), c(3,3), c(3,2), c(2,2))))
psf <- st_sf(geometry = st_sfc(p, crs = 4326))

ggplot(data = psf) + geom_sf(data = psf)
ggplot(data = psf) + geom_sf(data = psf, alpha = 0.5)

Using geom_line, it works:
lpt <- st_coordinates(lsf) %>% tbl_df()
ggplot() + geom_line(data = lpt, aes(x = X, y = Y), alpha = 0.2)

[edzer]

Since this concerns ggplot2, I'm adding @hadley

[hadley]

Yeah, the support for non-polygon features is not great. I'm aware of it and will look at in more detail when I'm next working on ggplot2 (so feel free to close this issue)

[Gustavoetal]

Error in geom_sf() : could not find function "geom_sf" still have this issue hot to fix?

[karldw]

@Gustavoetal, are you using the development version of ggplot2? The CRAN version doesn't have geom_sf yet. See the news for the next release.

[Gustavoetal]

Yes that was the case, I have the stable version and now is working, thanks

[seanhardison1]

Has alpha for linestrings been implemented yet in geom_sf?

[statnmap]

It does not seem so but a new issue has been opened on the ggplot2 side: https://github.com/tidyverse/ggplot2/issues/3589