Data Visualizations with ggplot2 in R/

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Adding Titles and Subtitles to Plots with ggplot2

Adding Titles and Subtitles to Plots with ggplot2

Learn how to add titles and subtitles to plots in ggplot2.

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Introduction to titles and subtitles in ggplot2

When creating a plot with ggplot2, adding a title and subtitle can provide context and clarity for the reader. The title can give an overview of the plotted main variables, while the subtitle can provide additional details. It is essential to choose a title and subtitle that accurately and concisely describes the plot’s content and provides enough information for the reader to understand the plot without being too long or complex.

Let’s first create a basic scatter plot using the Cars93 dataset and save it in an object called chart. Then, we can add a title and subtitle to this plot.

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chart <- ggplot(Cars93) +
    geom_point(aes(x = Horsepower, y = Price,
        color = Origin),size = 3)+  
    scale_color_manual(values = c("#03045E","#5DA9E9"))+  
    theme_bw()
chart
  • Line 1: We create a new object named chart and use the <- assignment operator for storing the graph in the chart object. We initialize a new ggplot object with the ggplot() function and pass the name of the Cars93 dataset. Using the + operator, we add a layer to the ggplot object.
  • Line 2: We use the geom_point() function to create a scatter plot where we use the aes() function for mapping the Horsepower variable to the x-axis and Price variable to the y-axis.
  • Line 3: We group the data by variable Origin using the color argument and change the size of points to 3 using the size argument.
  • Line 4: We use the scale_color_manual() function to specify different colors for the scatter plot.
  • Line 5: We use the theme_bw() function for changing the default gray theme
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