ggplot2 function scale_fill_stepsn colors do not match

Question

I have some codes that want to show a map with unequal color breaks and assign each category with a specific color. I used the scale_fill_stepsn function.

Here are my codes:

ggplot(data = rate) + 
    geom_sf(aes(fill = rate))+theme_bw()+
      scale_fill_stepsn(name = "Test Rate \n (n/1000)", 
                    colors =c("#999999","#6666FF", "#FFFF66","#FF6633"),
                    breaks = c(0,1, 10, 100),
                    labels=scales::label_number(accuracy=1),
                    show.limits = TRUE) +
    annotation_north_arrow(location = "tl", which_north = "true", 
        pad_x = unit(0.1, "in"), pad_y = unit(0.05, "in"),
        height = unit(1, "cm"),
        width = unit(1, "cm"),
        style = north_arrow_fancy_orienteering)+
    annotation_scale(location = "bl", width_hint = 0.2)

The exact colours I put in the function shows below, which do not match the colour in the result figure.

scales::show_col(c("#999999","#6666FF", "#FFFF66","#FF6633"))

data

It's easier to help you if you include a simple [reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) with sample input that can be used to test and verify possible solutions. — MrFlick, Dec 09 '22 at 20:36
Where do these annotation functions come from? If they're not needed for the specific question, you could remove those parts of the code so we don't have to install extra packages. You're setting up a gradient, but of colors that seemingly won't blend together nicely. An orange to blue gradient is going to look pretty muddy—seems like that's what you got as output — camille, Dec 09 '22 at 20:36
related: https://stackoverflow.com/questions/74224130/r-scale-fill-stepsn-error-in-breaks-and-colors — MrFlick, Dec 09 '22 at 20:44

score 1 · Accepted Answer · answered Dec 09 '22 at 21:11

If I add trans = scales::log10_trans(), to the scale_fill_stepsn I get better results for this reproducible example, because my breaks are log distributed, so my gradient should be too. Otherwise the gradient will apply linearly along 0:107, and most values will be in muddled gray land.

ggplot(data.frame(val = c(0, 1, 10, 100, 107), x = 1:5),
       aes(x, 0, fill = val)) +
  geom_tile() +
  scale_fill_stepsn(name = "Test Rate \n (n/1000)", 
                    colors =c("#999999","#6666FF", "#FFFF66","#FF6633"),
                    breaks = c(0,1, 10, 100), 
                    trans = scales::pseudo_log_trans(), #  ADDED THIS LINE
                    labels=scales::label_number(accuracy=1),
                    show.limits = TRUE)

With

Without

ggplot2 function scale_fill_stepsn colors do not match

1 Answers1