Setting color and fill Aesthetic Properties

This lesson is called Setting color and fill Aesthetic Properties, part of the Fundamentals of R course. This lesson is called Setting color and fill Aesthetic Properties, part of the Fundamentals of R course.

Transcript

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# Load Packages -----------------------------------------------------------

library(tidyverse)

# Import Data -------------------------------------------------------------

penguins <- read_csv("penguins.csv")

penguin_bill_length_by_island <-
  penguins |>
  group_by(island) |>
  summarize(mean_bill_length = mean(bill_length_mm, na.rm = TRUE)) |>
  arrange(mean_bill_length)

# Setting color and fill Aesthetic Properties -----------------------------

# We add the color argument within aes() so that
# the data in that variable is mapped to those aesthetic properties.

# With this code, the island variable is mapped to the aesthetic property color

ggplot(
  data = penguins,
  mapping = aes(
    x = bill_length_mm,
    y = bill_depth_mm,
    color = island
  )
) +
  geom_point()

# Let's try the same thing with our bar chart

ggplot(
  data = penguin_bill_length_by_island,
  mapping = aes(
    x = island,
    y = mean_bill_length,
    color = island
  )
) +
  geom_col()

# That didn't work! Let's try fill instead.

ggplot(
  data = penguin_bill_length_by_island,
  mapping = aes(
    x = island,
    y = mean_bill_length,
    fill = island
  )
) +
  geom_col()

Your Turn

# Load Packages -----------------------------------------------------------

library(tidyverse)

# Import Data -------------------------------------------------------------

penguins <- read_csv("penguins.csv")

# Setting color and fill Aesthetic Properties -----------------------------

# Take your graph that uses geom_col() and make the inside of each bar a different color.

# YOUR CODE HERE

# Make your scatterplot from before with flipper length on the x axis and body mass on the y axis
# but make the points different colors based on the island variable

# YOUR CODE HERE

Learn More

You may want to review Chapter 11 from R for Data Science, which includes a section on mapping data to color and fill aesthetics. Chapter 2 of Fundamentals of Data Visualization has a similar discussion. So does Chapter 3 of Data Visualization: A Practical Introduction.

Chapter 11 of ggplot2: Elegant Graphics for Data Analysis is also a good place to learn about color and fill scales.

Have any questions? Put them below and we will help you out!

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J.R. Moller • March 23, 2026

Pending approval

For both graphics, I had to include "island" with the quotes for it to work. Additionally, it didn't default to the three colors but instead did a single color for the fill. I'm not sure what I did wrong. Here's my code for the scatterplot: ggplot( data = penguins, mapping = aes( x = flipper_length_mm, y = body_mass_g, color = "island" ) ) + geom_point()

J.R. Moller • March 23, 2026

Pending approval

My version of R (4.5.3) crashed and errored out. When it rebooted, everything seems to work properly now. Please disregard my last comment (and this one, too).