coord_proj is throwing a "Not implemented error"

[colinaverill]

Below is some simplified code to plot a world map using ggplot2. This code was working fine for me until April, at which point I started getting Error: not implemented. Line by line testing links this outcome to the coord_proj() line. There was some discussion of this on stackoverflow, but no definitive solution was found. Reproducible example and error messages below.

world <- ggplot2::map_data("world")
world <- world[world$region != "Antarctica",]
gg <- ggplot()
gg <- gg + geom_cartogram(data=world, map=world,
                          aes(x=long, y=lat, map_id=region))
gg <- gg + coord_proj("+proj=wintri")
gg

Error messages:

Error: Not implemented
Run `rlang::last_error()` to see where the error occurred.
> rlang::last_error()
<error/rlang_error>
Not implemented
Backtrace:
  1. (function (x, ...) ...
  2. ggplot2:::print.ggplot(x)
  4. ggplot2:::ggplot_gtable.ggplot_built(data)
  5. base::Map(...)
  6. base::mapply(FUN = f, ..., SIMPLIFY = FALSE)
  8. l$draw_geom(d, layout)
  9. ggplot2:::f(..., self = self)
 10. self$geom$draw_layer(data, self$geom_params, layout, layout$coord)
 11. ggplot2:::f(..., self = self)
 12. base::lapply(...)
 13. ggplot2:::FUN(X[[i]], ...)
 16. ggalt:::f(...)
 17. ggplot2::coord_munch(coord, map, panel_scales)
 18. coord$backtransform_range(range)
 19. ggplot2:::f(..., self = self)
Run `rlang::last_trace()` to see the full context.

[yutannihilation]

Could you file this issue on ggalt's repo? At the moment, I'm not sure if this is a bug on ggalt's side or on ggplot2's side, but this sounds ggalt needs to implement backtransform_range().

[colinaverill]

Sure thing. Thanks.

…

On Mon, Jun 22, 2020 at 4:18 PM Hiroaki Yutani ***@***.***> wrote: Could you file this issue on ggalt's repo? At the moment, I'm not sure if this is a bug on ggalt's side or on ggplot2's side, but this sounds ggalt needs to implement backtransform_range(). — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#4082 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB7I4AUE5ZT2BZPWWJ4FEQTRX5R3VANCNFSM4OESRFFQ> .

[yutannihilation]

Ah, this one seems the same issue: hrbrmstr/ggalt#62

[clauswilke]

Not sure what coord_proj() does but I suspect there'll be little need for it once we merge #3659. I can try to finish this off in the next few days. Just one last issue remaining.

[clauswilke]

Sorry, I was overly optimistic. Winkel tripel is not supported by {sf} (due to lack of inverse transformation) and therefore won't be possible with coord_sf().

If you want to make a map using this projection, I suggest you follow this tutorial:
https://wilkelab.org/practicalgg/articles/Winkel_tripel.html