R ggplot - Plot your data

BIG method courses

Authors
Affiliations

BIG

Bioinformatics Interest Group

Fabian Kugler

BIG Gitlab

Introduction

Data visualization is a critical skill in data science, helping us to make sense of complex datasets and effectively communicate insights. This course is designed to introduce you to ggplot2, a powerful and flexible plotting system in R that is widely used by data scientists, researchers, and analysts. If you’re new to R or data visualization, you’re in the right place—this course will guide you step-by-step, from foundational concepts to creating complex visualizations.

Why ggplot2?

ggplot2 is part of the tidyverse—a collection of R packages designed for data science—which means it integrates well with other tools like dplyr and tidyr for data manipulation. One of ggplot2’s most appealing features is its flexibility, enabling users to create high-quality, professional-looking graphs while following a layered approach to data visualization. With ggplot2, you can go from simple bar plots and scatter plots to complex multi-layered plots, all within a single framework.

Here are some of the things you’ll be able to accomplish by the end of this course:

  • Understand the grammar of graphics: ggplot2 is based on a unique approach to plotting called the “Grammar of Graphics,” which enables you to systematically layer elements of a plot. Once you understand this concept, you can add, remove, or adjust layers to customize your plots easily.

  • Create a wide variety of charts and plots: You’ll learn to make everything from simple histograms, bar plots, and scatter plots to more complex visualizations like box plots, line charts, and heatmaps. Each plot type serves a unique purpose and helps communicate different types of data effectively.

  • Customize plots for clarity and impact: The course will guide you through customizing plot aesthetics, including colors, labels, and themes, so that your visualizations align with your communication goals and audience preferences. You’ll also learn how to adjust axis labels, add titles, and control legends to make your plots intuitive and visually appealing.

  • Handle and visualize complex datasets: As you gain confidence, you’ll learn how to use ggplot2 to create multi-faceted plots that can showcase multiple variables at once. This includes faceted plots, which allow for side-by-side comparisons, and techniques for handling and visualizing time series, categorical, and continuous data.

  • Save and share your visualizations: In addition to creating plots in R, you’ll also learn how to save your visualizations in various formats suitable for presentations, reports, or publications.

Course Outline

Here’s a brief overview of what’s covered in the course:

  1. Introduction to ggplot2 and the Grammar of Graphics: We’ll start with the basics of ggplot2, understanding the “aesthetic mapping” and how to layer different components to create meaningful visualizations.

  2. Basic Plot Types: You’ll get hands-on practice creating foundational plot types like bar charts, line graphs, and scatter plots, building confidence in interpreting different data structures.

  3. Working with Colors, Labels, and Themes: Visual appeal is essential in good data visualization. You’ll learn how to apply color palettes, adjust themes, and add labels and annotations to make your plots more engaging and informative.

  4. Faceting and Grouping Data: To handle more complex data, we’ll dive into faceting techniques that enable you to create multi-panel plots, making it easier to compare subsets of data.

  5. Advanced Plotting Techniques: For those ready to go further, we’ll explore specialized plots such as box plots, violin plots, and heatmaps, and look at how to handle data distributions and time series.

  6. Exporting and Sharing Your Plots: Finally, we’ll cover how to export your work in different formats, including high-resolution images for presentations or scalable vector graphics for reports.

Who is this Course For?

This course is ideal for beginners who have little to no experience with R or ggplot2 but are interested in data science and want to build their data visualization skills. By the end of the course, you’ll not only be able to create a wide range of plots but also understand how to tailor each visualization to best suit your audience and message.

Get ready to transform raw data into insightful, beautiful visualizations! Whether you’re preparing for a presentation, report, or data analysis project, ggplot2 will become an invaluable tool in your data science toolkit. Let’s get started!