Enhancing visualizations (part I)

Week 5

Wednesday February 4th, 2026

A fuzzy monster in a beret and scarf, critiquing their own column graph on a canvas in front of them while other assistant monsters (also in berets) carry over boxes full of elements that can be used to customize a graph (like themes and geometric shapes). In the background is a wall with framed data visualizations. Stylized text reads 'ggplot2: build a data masterpiece.'

Artwork by Allison Horst

Pre-class Prep

A. Install required packages

install.packages("paletteer") # a comprehensive collection of color palettes in R using a common interface
install.packages("viridis") # Colorblind-Friendly Color Maps for R
install.packages("RColorBrewer") # ColorBrewer Palettes
install.packages("tigris") # for downloading and using Census TIGER/Line shapefiles in R
install.packages("sf") # provides simple features access in R

B. Download data

  1. Download County-level precipitation data (Jan 2020 - Dec 2024) for the contiguous U.S, made available by NOAA National Centers for Environmental Information (NCEI) (you do not need to adjust any of the drop down selections; find the download buttons just beneath the rendered map – choose the CSV option)
    • rename the data file as NCEI-county-jan20-dec24-precip.csv and save it to your class repo at the file path: EDS-240-class-examples/week5/data/NCEI-county-jan20-dec24-precip.csv

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/week5/ folder.

  2. Review the data wrangling code under the ## Setup section of template 5.3 and make note of any questions you might have (no data wrangling necessary in template 5.2). 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 5.1: good data viz NA NA
Lecture 5.2: colors 5.2 template 5.2 key
Lecture 5.3: choropleth 5.3 template 5.3 key

Pre-discussion Prep

A. (OPTIONAL) Bring a cool data viz!

This week’s discussion section will be a time to explore, share, and discuss “non-standard” chart types, as well as those that present data using the fundamental chart types we’ve already discussed in different and exciting ways. You’ll have time to browse some data viz during section, but it would be great to bring any inspiring examples you might have come across already.

B. (OPTIONAL) Get yourself a Bluesky account

Bluesky is quickly becoming the Twitter replacement for data science community members to connect, share, and learn together. You can stay up to date on #TidyTuesday submissions and follow many of the great data viz folks in the field. Check out the resources page for more information on how to get started.

Discussion Materials

Discussion Slides Exercise instructions Exercise solutions
D5 slides: “non-standard” chart types NA NA

Assignment Reminders

Assignment Type Assignment Title Date Assigned Date Due
FPM Final Project Milestone #2 Wed 01/28/2026 Wed 02/04/2026, 11:59pm PT
SR Mid-course reflection (SR #2) Wed 02/04/2026 Fri 02/06/2026, 11:59pm PT
HW Homework #3 Wed 02/04/2026 Wed 02/11/2026, 11:59pm PT