geom_vline() ask for origin when combined with coord

When I combine geom_vline and coord_polar with a Date axis, it asks for origin. It works fine when coord_polar is not called.

library(ggplot2)

data.frame(
  a = seq.Date(as.Date("2022-01-01"), as.Date("2022-01-31"), by= "1 day"),
  b = runif(31)
) |> 
  ggplot(aes(x=a, y=1, fill=b)) 
  geom_tile(show.legend = FALSE) 
  geom_vline(xintercept=as.Date("2022-01-15")) 
  coord_polar()
#> Error in as.Date.numeric(value): 'origin' must be supplied

^{Created on 2022-11-07 with reprex v2.0.2}

What is origin in this context?

CodePudding user response：

I think coord_polar() is not equipped for working with dates. Just transform the xintercept to numeric and it should just work (TM):

library(ggplot2)

data.frame(
  a = seq.Date(as.Date("2022-01-01"), as.Date("2022-01-31"), by= "1 day"),
  b = runif(31)
) |> 
  ggplot(aes(x=a, y=1, fill=b)) 
  geom_tile(show.legend = FALSE)  
  geom_vline(xintercept=as.numeric(as.Date("2022-01-15")), size=2, color="red")  
  coord_polar()

^{Created on 2022-11-07 with reprex v2.0.2}

Btw I really hope this is just a MVE, a circular graph with dates looks really confusing imo.