Fundamental Chart Types (relationships), What Makes a Good Viz

Week 4

Wednesday January 28th, 2026

A group of fuzzy round monsters with binoculars, backpacks and guide books looking up a graphs flying around with wings (like birders, but with exploratory data visualizations). Stylized text reads 'ggplot2: visual data exploration.' Learn more about ggplot2.

Artwork by Allison Horst

Pre-class Prep

A. Install required packages

install.packages("metajam") # for downloading and reading data and metadata from repositories in the DataONE network
install.packages("ggExtra") # {ggplot2} extension which can be used to add marginal histograms/boxplots/density plots to ggplot2 scatterplots
install.packages("ggdensity") # {ggplot2} extension providing more interpretable visualizations of density estimates based on highest density regions (HDRs)

B. Download data

Save data to your class repo at EDS-240-class-examples/week4/:

Lecture Dataset title Download link Notes
4.1 Continuous precipitation and stream chemistry data, Hubbard Brook Ecosystem Study, 1963 – ongoing we’ll use the {metajam} package to download the data programmatically from DataONE (see step C, below, for setup instructions), however, in the event that the API is down, you can access a backup copy on Google Drive Find the full data package on DataONE; DataONE is a community driven project providing access to data across multiple member repositories, supporting enhanced search and discovery of Earth and environmental data.

C. Download .qmd templates & review data wrangling code

  1. Download all necessary templates (links in the table below) and save them to a EDS-240-data-viz-examples/week4/ folder.

  2. Review the data wrangling code under the ## Setup section of each template file and make note of any questions you might have. Due to time constraints, we won’t be live-coding our way through the data wrangling code in class. However, we’ll reserve some time to answer any questions before we jump into data viz .

Lecture Materials

Lecture slides Code-along template Code-along key
Lecture 4.1: visualizing numeric relationships 4.1 template 4.1 key
Lecture 4.2: good data viz NA NA

Pre-lab Prep

A. Prepare a week4-lab.qmd file

Add a new blank file to your class repo at the following location: EDS-240-class-examples/week4/week4-lab.qmd. Fill out the necessary YAML information (title, author, date + any other information you find helpful).

Lab Materials

TODO
  • create new lab exercise/content for practicing fundamental chart types – hackathon style? provide a few different data sets, split into groups that get randomly assigned a dataset; must consider the chart types covered in lecture over the past 3 weeks and build an appropriate viz?
Lab Slides Exercise instructions Exercise solutions
Lab 4 slides: ggplot themes Lab 4 exercise: USDM plot theme Lab 4 solution

Assignment Reminders

Assignment Type Assignment Title Date Assigned Date Due
HW Homework #2 Wed 01/21/2026 Wed 01/28/2026, 11:59pm PT
FPM Final Project Milestone #2 Wed 01/28/2026 Wed 02/04/2026, 11:59pm PT