Data Viz II

Lecture 4

Dr. Elijah Meyer

Duke University
STA 199 - Fall 2023

2023-09-07

Checklist

– Are you in the GitHub organization?

– Go to our GitHub. This link is also at the bottom of our slides. Make sure you log into Git to see your repos!

– Do you see hw-01 & ae-03? If not, this is your final warning to come talk with us!

– Here is a public repo for today if needed: ae-03

Do not click and clone the public repo if you have a personalized repo. This is the last class we will have a public repo.

– Keeping up with the Prepare link on course website

– Try cloning AE-03! We will also do this together as a class.

Goals for today

– More Plots!

– More practice with R

Announcements

HW-1 is out now; due September 12th at 11:59 on Gradescope.

– Mark all the pages associated with exercise

– Do not select any pages of your PDF submission to be associated with the “Workflow & formatting” question.

Announcements

– AEs will be checked for “completion” next week

– All due on Friday at 11:59 pm

– Answer keys will be posted shortly after

Announcements

R update should be coming soon

Warm Up

Practice reading the following code as a sentence

mtcars: The data was extracted from the 1974 Motor Trend US magazine, and comprises fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models).

    mtcars |>
        ggplot(
        aes(
             x = mpg, y = wt)
               ) +
        geom_point()

Warm Up: Syle Guide

Based on the style guide, how can the code below be improved?

      iris |>
        filter(Species == "setosa") |>
        ggplot(aes(x = Sepal.Width, y = Sepal.Length))+ geom_point()

Warm Up: Syle Guide

– + should always have a space before it, and should be followed by a new line

      iris |>
        filter(Species == "setosa") |>
        ggplot(aes(x = Sepal.Width, y = Sepal.Length)) +
        geom_point()

ae-02

Recreate Graph

Recap of AE

– Construct plots with ggplot().

– Layers of ggplots are separated by +s.

– Aesthetic attributes of a geometries (color, size, transparency, etc.) can be mapped to variables in the data or set by the user.

– Use facet_wrap() when faceting (creating small multiples) by one variable and facet_grid() when faceting by two variables.