Title, subtitle, caption and tag [GGPLOT2]

When using ggplot2 you can set a title, a subtitle, a caption and a tag. There are two ways to add titles: using ggtitle or labs function. The former is only for titles and subtitles and the latter also allows adding tags and captions.

Title

Option 1. Using ggtitle

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  ggtitle("Title of the plot using ggtitle()")

Adding a title in ggplot2 with ggtitle

Option 2. Using labs

You can also use the labs function to add the title.

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(title = "Title of the plot using labs()")

Title in ggplot2 using labs

Title position

The title position can be set respect to the whole plot instead of the panel with the plot.title.position component of the theme function. Default value is "panel". This configuration also applies to the subtitle.

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(title = "Title on the plot margin") + 
  theme(plot.title.position = "plot")

Customize the title position in ggplot2

Subtitle

You can add a subtitle the same way you added the title, but with the subtitle argument.

Add a subtitle in ggplot2

Option 1. Using ggtitle

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) +  
  ggtitle("Title of the plot",
          subtitle = "Subtitle of the plot")

Subtitle in ggplot2 using labs

Option 2. Using labs

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(title = "Title of the plot",
       subtitle = "Subtitle of the plot")

Caption

A caption can be used to describe the figure. You can add it with the caption argument of the labs function.

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(title = "Title of the plot",
       subtitle = "Subtitle of the plot",
       caption = "This is the caption")

Adding a caption in ggplot2

The plot.caption.position of the theme function allows aliging the caption to the panel ("panel", default) or the whole plot (“plot”).

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(caption = "This is the caption") +
  theme(plot.caption.position = "plot",
        plot.caption = element_text(hjust = 0))

Changing the caption position in ggplot2

Note that the default for the caption is right alignment, so you can set hjust = 0 to move the caption to the left of the whole plot.

Tag

Adding a tag to the plot in ggplot2

Tags are useful to indicate the figure numbering. You can add it with the tag argument of the labs function.

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(title = "Title of the plot",
       subtitle = "Subtitle of the plot",
       caption = "This is the caption",
       tag = "Fig. 1")

Changing the tag position in ggplot2

Tag position

The position of the tag can be set with the plot.tag.position component of the theme function. Possible values are "topleft" (default), "top", "topright", "left", "right", "bottomleft", "bottom" or "bottomright".

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(tag = "Fig. 1") +
  theme(plot.tag.position = "bottomright)

Further styles and adjustments

The titles, subtitles, captions and tags can be customized with the plot.title, plot.subtitle, plot.caption and plot.tag components of the theme function, making use of element_text. You can modify the color, the font family, the text size, the text face, the angle or the vertical and horizontal adjustment for each text as in the example below.

Styling the titles in ggplot2, such as modifying the color, size, face, family, lineheight and margins

# install.packages(ggplot2)
library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_area(fill = rgb(0, 0.5, 1, alpha = 0.5)) + 
  labs(title = "Title of the plot",
       subtitle = "Subtitle of the plot",
       caption = "This is the caption",
       tag = "Fig. 1") + 
  theme(plot.title = element_text(family = "serif",              # Font family
                                  face = "bold",                 # Font face
                                  color = 4,                     # Font color
                                  size = 15,                     # Font size
                                  hjust = 1,                     # Horizontal adjustment
                                  vjust = 1,                     # Vertical adjustment
                                  angle = -10,                   # Font angle
                                  lineheight = 1,                # Line spacing
                                  margin = margin(20, 0, 0, 0)), # Margins (t, r, b, l)
        plot.subtitle = element_text(hjust = 0),    # Subtitle customization
        plot.caption = element_text(hjust = 0.25),  # Caption customization
        plot.tag = element_text(face = "italic"),   # Tag customization
        plot.title.position = "plot",               # Title and subtitle position ("plot" or "panel")
        plot.caption.position = "panel",            # Caption position ("plot" or "panel")
        plot.tag.position = "top")                  # Tag position