Hexadecimal colors in ggplot not colored as expected

Question

EDIT:

I asked a question which boils down to this:

\"How can I get ggplot to use hexadecimal colors?\"

The answer by MrFick was exce

Answer 1

If you want to specify a literal color value in a geom_segment, you should not include it in the aes(). For example using this test data

DF_for_plotting <- data.frame(
    variable=rep("StrpCnCor",4),
    value=c(0, 50.79330935, 81.127731, 100)
)

you can do

ggplot() +
    geom_segment(data=DF_for_plotting, aes(x=value[1], xend=value[2]-0.001, y=1, yend=1), colour="green", size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[2], xend=value[3]-0.001, y=1, yend=1), colour="blue", size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[3], xend=value[4]-0.001, y=1, yend=1), colour="red", size=10)

or with hex colors

ggplot() +
    geom_segment(data=DF_for_plotting, aes(x=value[1], xend=value[2]-0.001, y=1, yend=1), colour="#9999CC", size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[2], xend=value[3]-0.001, y=1, yend=1), colour="#66CC99", size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[3], xend=value[4]-0.001, y=1, yend=1), colour="#CC6666", size=10)

Although because you're not mapping anything to the color aesthetic, no legend will be provided.

When you put it in the aes(), you're not specifying a literal value, you are just specifying a literal value to associate with a color it doesn't matter if you use aes(color="red") or aes(color="determination"); it just treats it as a literal character value and will use it's own color palate to assign a color to that character value. You can specify your own colors with scale_fill_manual For example

ggplot() +
    geom_segment(data=DF_for_plotting, aes(x=value[1], xend=value[2]-0.001, y=1, yend=1, colour="a"), , size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[2], xend=value[3]-0.001, y=1, yend=1, colour="b"), , size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[3], xend=value[4]-0.001, y=1, yend=1, colour="c"),  size=10) + 
    scale_color_manual(values=c(a="green",b="blue",c="red"))

ggplot() +
    geom_segment(data=DF_for_plotting, aes(x=value[1], xend=value[2]-0.001, y=1, yend=1, colour="a"), , size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[2], xend=value[3]-0.001, y=1, yend=1, colour="b"), , size=10) +
    geom_segment(data=DF_for_plotting, aes(x=value[3], xend=value[4]-0.001, y=1, yend=1, colour="c"),  size=10) + 
    scale_color_manual(values=c(a="#9999CC",b="#66CC99",c="#CC6666"))

Here i called the three groups "a", "b", and "c" but you could also call then "green","blue","red" if you want -- it just seems odd to have a legend that tells you what color is green.