Description
Hi the use case where i encountered this bug was when i was trying to plot county borders overlay-ed with colored lines of specific routes. I tried to plot the countries with geom_map.
The example is a bit complicated therefore a small example that produces exactly the same traceback
My idea was to use the NA colour to give a specific colour to one dataset (the country borders) and then use the color scale to give colours to the other dataset. So one dataset has only NA. I realize this is already a work around for plotting the borders but setting the colour arugment for geom_map did not seem to work:
require(ggplot2)
crimes <- data.frame(state = tolower(rownames(USArrests)), USArrests)
crimes$Murder<-NA
states_map <- map_data("state")
ggplot(crimes, aes(map_id = state)) +
geom_map(aes(fill = Murder), map = states_map, color="green") +
expand_limits(x = states_map$long, y = states_map$lat) +
scale_fill_hue(na.value=NA)produces an empty plot instead of green borders as expected. Using colour mapped as an aes seams to work:
ggplot(crimes, aes(map_id = state)) +
geom_map(aes(fill = Murder, colour=Murder), map = states_map) +
expand_limits(x = states_map$long, y = states_map$lat) +
scale_fill_hue(na.value=NA)but then i run into this problem below there one dataset has only NA in the colour column
> a<-data.frame(x=1:10, y=1:10, col=1:10);
> b<-data.frame(x=1:10, y=10:1, col=NA);
> ggplot(data=a,aes(x=x,y=y,colour=col))+geom_point()+geom_point(data=b)+scale_colour_gradient(na.value="red")
Error: Discrete value supplied to continuous scale
> traceback()
12: stop("Discrete value supplied to continuous scale", call. = FALSE)
11: train_continuous(x, range)
10: scale$range$train(x)
9: scale_train.continuous(scale, df[[aesthetic]])
8: scale_train(scale, df[[aesthetic]])
7: FUN(X[[1L]], ...)
6: lapply(scales$scales, scale_train_df, df = df)
5: FUN(X[[2L]], ...)
4: lapply(data, scales_train_df, scales = npscales)
3: ggplot_build(x)
2: print.ggplot(list(data = list(x = 1:10, y = 1:10, col = 1:10),
layers = list(<environment>, <environment>), scales = <S4 object of class "Scales">,
mapping = list(x = x, y = y, colour = col), options = list(
labels = list(x = "x", y = "y", colour = "col")), coordinates = list(
limits = list(x = NULL, y = NULL), wise = FALSE), facet = list(
shrink = TRUE), plot_env = <environment>))
1: print(list(data = list(x = 1:10, y = 1:10, col = 1:10), layers = list(
<environment>, <environment>), scales = <S4 object of class "Scales">,
mapping = list(x = x, y = y, colour = col), options = list(
labels = list(x = "x", y = "y", colour = "col")), coordinates = list(
limits = list(x = NULL, y = NULL), wise = FALSE), facet = list(
shrink = TRUE), plot_env = <environment>))
But it seems to work as soon as the colour column of the b dataset does contain one non na value
> a<-data.frame(x=1:10, y=1:10, col=1:10);b<-data.frame(x=1:10, y=10:1, col=c(1,rep(NA,9))); ggplot(data=a,aes(x=x,y=y,colour=col))+geom_point()+geom_point(data=b)+scale_colour_gradient(na.value="red")> sessionInfo()
R version 2.15.0 (2012-03-30)
Platform: x86_64-pc-linux-gnu (64-bit)
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=C LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] ggplot2_0.9.0
loaded via a namespace (and not attached):
[1] colorspace_1.1-1 dichromat_1.2-4 digest_0.5.2 grid_2.15.0
[5] MASS_7.3-17 memoise_0.1 munsell_0.3 plyr_1.7.1
[9] proto_0.3-9.2 RColorBrewer_1.0-5 reshape2_1.2.1 scales_0.2.0
[13] stringr_0.6