Home » How to Change Line Colors in ggplot2 (With Examples)

How to Change Line Colors in ggplot2 (With Examples)

by Erma Khan

You can use the following basic syntax to specify line colors in ggplot2:

ggplot(df, aes(x=x, y=y, group=group_var, color=group_var)) + 
    geom_line() +
    scale_color_manual(values=c('color1', 'color2', 'color3'))

The following example shows how to use this syntax in practice.

Example: Change Line Colors in ggplot2

Suppose we have the following data frame in R:

#create data frame
df frame(store=c('A', 'A', 'A', 'B', 'B', 'B', 'C', 'C', 'C'),
                 week=c(1, 2, 3, 1, 2, 3, 1, 2, 3),
                 sales=c(9, 12, 15, 7, 9, 14, 10, 16, 19))

#view data frame
df

  store week sales
1     A    1     9
2     A    2    12
3     A    3    15
4     B    1     7
5     B    2     9
6     B    3    14
7     C    1    10
8     C    2    16
9     C    3    19

Now suppose we create the following line plot in ggplot2 to visualize the total sales by week and by store:

library(ggplot2)

#create line plot
ggplot(df, aes(x=week, y=sales, group=store, color=store)) + 
    geom_line(size=2)

By default, ggplot2 uses a default color palette with red, green, and blue for the lines.

However, you can use the scale_color_manual() function to specify your own colors for the lines:

library(ggplot2)

#create line plot
ggplot(df, aes(x=week, y=sales, group=store, color=store)) + 
    geom_line(size=2) +
    scale_color_manual(values=c('orange', 'pink', 'red'))

The colors are now orange, pink, and red.

Note that you can also use hex color codes to specify the colors:

library(ggplot2)

#create line plot
ggplot(df, aes(x=week, y=sales, group=store, color=store)) + 
    geom_line(size=2) +
    scale_color_manual(values=c('#063970', '#A69943', '#7843a6'))

The colors now correspond to the specific hex color codes that we chose.

Additional Resources

The following tutorials explain how to perform other common tasks in ggplot2:

How to Rotate Axis Labels in ggplot2
How to Change Point Size in ggplot2
How to Add Text to ggplot2 Plots

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