ggplot scale_x_continuous with symbol: make bold

Question

Here is the issue: I am using ggplot to to make a graph in which the x axis ranges from -90 to 90 degrees. I have successfully used a function to add degree sym

Answer 1

I read a comment here that mentions that labels take a character value. The output of your function was an expression. Changing add_degree() to the following outputs character values instead of an expression and seems to work for me:

add_degree <- function(x) {
  paste(x, "º",sep = "")
}

Here is my output for sessionInfo()

R version 3.0.3 (2014-03-06)
Platform: x86_64-apple-darwin10.8.0 (64-bit)

locale:
[1] en_CA.UTF-8/en_CA.UTF-8/en_CA.UTF-8/C/en_CA.UTF-8/en_CA.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods  
[7] base     

other attached packages:
[1] ggplot2_1.0.0

loaded via a namespace (and not attached):
 [1] colorspace_1.2-4 digest_0.6.4     grid_3.0.3      
 [4] gtable_0.1.2     labeling_0.2     MASS_7.3-31     
 [7] munsell_0.4.2    plyr_1.8.1       proto_0.3-10    
[10] Rcpp_0.11.1      reshape2_1.4     scales_0.2.4    
[13] stringr_0.6.2    tools_3.0.3   

Answer 2

I'm reusing the function taken from a similar question, which only requires a little adjustment.

make_labels <- function(value) {
  x <- as.character(value)
  do.call(expression, lapply(x, function(y) bquote(bold(.(y))^degree)))
}

Now, in your ggplot call instead of add_degree use labels = make_labels and you'll get