path + polar coord + single value = error

[fdelaunay]

Hi,

I've detected an unexpected behavior. I've briefly browsed the issues and don't think it was reported yet. Please excuse me it was. Here is how to reproduce it:

d <- expand.grid(sectors = 1:2, facets = 1:2 )
d$value <- c(5,6,7, NA)

library(ggplot2)
g <- ggplot(d, aes(x=sectors)) + geom_path(stat='identity', aes(y=value, group=1)) + facet_wrap( ~ facets)

#ok
g
#crash
g + coord_polar()

I understand that polar plots must be used with extreme precautions but I though that this bug looks simple enough to be reported :)

ggplot rules!

François

[BrianDiggs]

With your example, I didn't get a crash, but I did get

> g + coord_polar()
Error: replacement has 1 row, data has 0
In addition: Warning message:
Removed 1 rows containing missing values (geom_path). 

It does seem like a bug.

[fdelaunay]

No, it doesn't properly "crash". But when executed by Shiny, it kills the application :(

[SamGG]

An error stops further execution.

IMHO it is a border effect bug. The polar code has certainly not been tested in that particular case where no path could be displayed. Adding a point to each path leads to "no crash" ;-)

d <- expand.grid(sectors = 1:3, facets = 1:2 )
d$value <- c(2,3,5,6,7, NA)

library(ggplot2)
g <- ggplot(d, aes(x=sectors)) + 
geom_path(stat='identity', aes(y=value, group=1)) + 
facet_wrap( ~ facets)

#ok
g
# NO MORE crash
g + coord_polar()

[fdelaunay]

@SamGG changing data is cheating :D

Other option is to remove a point ! it doesn't produce error when there is no point:

d <- expand.grid(sectors = 1:2, facets = 1:2 )
d$value <- c(5,6,NA, NA)

library(ggplot2)
g <- ggplot(d, aes(x=sectors)) + geom_path(stat='identity', aes(y=value, group=1)) + facet_wrap( ~ facets)

#ok
g
#error
g + coord_polar() 

I will post something on Shiny g-group to understand why this error stops Shiny, not others.