# Concepts of the `{ggplot2}`

Package Pt. 2

12:00-12:30

View slides in full screen | Run the code yourself

# Outline

- Facet Types
- Wrapped Facets
- Facet Multiple Variables
- Facet Options: Cols + Rows
- Facet Options: Free Scaling
- Facet Options: Switch Labels

- Gridded Facets
- Facet Multiple Variables
- Facet Options: Proportional Spacing

- Scales
- Continuous vs. Discrete in {ggplot2}
- Aesthetics + Scales
`scale_x|y_continuous`

`scale_x|y_date`

`scale_x|y_date`

with`strftime()`

`scale_x|y_discrete`

- Discrete or Continuous?
`scale_color|fill_discrete`

- Inspect Assigned Colors
`scale_color|fill_manual`

`scale_color|fill_carto_d`

- Coordinate Systems
- Cartesian Coordinate System
- Changing Limits
- Clipping
- Fixed Coordinate System
- Flipped Coordinate System
- Circular Coordinate System
- Transform a Coordinate System
- Spatial Coordinate (Reference) Systems

# Recap

`facet_*()`

functions allow to create small multiples`scale_*()`

functions translate between aesthetics and properties- use
`*_continuous()`

for numerical data - … and
`*_discrete()`

for categorical data - use
`scale_color|fill_*()`

to customize data-related colors `coord_*()`

functions interpret the positional aesthetics, e.g. create polar plots or work with spatial projections- be careful when adjusting axis limits:
`scale_*_continuous(limits)`

removes the data outside the range`coord_*(*lim)`

keeps the data and zooms into the range

# Exercises

## Exercise 1

- Open the script
`exercises/03_concepts_pt2_ex1.qmd`

(or the`.rmd`

). - Have a look at the visualization in the folder
`exercises/3-1-astronaut-viz`

that shows the cumulative time that cosmo- and astronauts have spent in outer space. The data also contains information on the year of their first and last travel, respectively.

- Together with your group, discuss which layers and modifications are needed to create such a chart with
`{ggplot2}`

. - Note down the aesthetics, geometries, and scales used for each element of this graphic.
- What is the coordinate system? Have any adjustments been made?
- Which theme was used and how was it modified?

- Together with your group, discuss which layers and modifications are needed to create such a chart with

**→ Solution**

## Exercise 2

- Open the script
`exercises/03_concepts_pt2_ex2.qmd`

(or the`.rmd`

). - Create a circular lollipop plot of reported bike shares per season.
- The data is not in the right format as there are no totals. How can you solve it?
- Remove all legend elements (with a single line of code).
- How can you add the labels next to the starting point of each lollipop?
- How could you add a baseline?

**→ Solution**