Fix typography in axis labels

Question

Preamble: I want to create publication-grade graphics from R without postprocessing. Other researchers at my institute always perform postprocessing in a graphics software (such as Adobe Illustrator). I am hoping to avoid this.

My gripe is that R doesn’t use the correct minus sign for negative numbers (especially in plot axes):

plot(-20:-1, rnorm(20) + 1 : 20)

(I’ve circled the offenders for your consideration.)

As somewhat of a typography nerd (it’s true! Check my Careers CV!) this is unacceptable. I need to use the correct Unicode character ᴍɪɴᴜꜱ ꜱɪɢɴ (U+2212, “−”) here. A friend of mine achieves this by replacing all minus signs in Adobe Illustrator prior to publication but I can’t help but think that there must be a better way – from within R – to accomplish this; and one that doesn’t force me to manually replace all axis labels.

(I’m not currently using ggplot2 but if there’s a solution which only works with ggplot2 I’ll gladly take it.)

Answer 1

Perhaps draw the axis and labels manually, rather than accepting the defaults?

plot(-20:-1, rnorm(20) + 1 : 20, xaxt="n")
Axis(-20:-1, at=seq(-20,-5,5), side=1,
  labels=paste("\U2212",seq(20,5,-5),sep=""))

Answer 2

Another way which is almost the same as the one provided by Joshua Ulrich, except that you can let R compute the axis ticks :

plot(-20:-1, rnorm(20) + 1 : 20, xaxt="n")
at <- axTicks(1, usr=par("usr")[1:2])
labs <- gsub("-", "\U2212", print.default(at))
axis(1, at=at, labels=labs)