FAQ and wrap-up

Data Visualisation with R

👩🏻‍💻 Emi Tanaka @ Monash University

  • emi.tanaka@monash.edu
  • @statsgen
  • github.com/emitanaka
  • emitanaka.org



28th November 2022 Australasian Applied Statistics Conference 2022

File formats

Are these figures different?

Both figures used the same code below to produce the figure:

ggplot(cars, aes(speed, dist)) + geom_point()
but I saved one to a png file and the other as a svg file.

Communicating Figures

  • There are two main formats for graphics:
    • Raster formats contain description of each pixel. Common formats are:
      • jpg (or jpeg) uses a lossy data compression that results in some loss of information but usually a small file size.
      • png uses a lossless data compression and works well if the image has uniform colors.
    • Vector formats contain a geometric description and hence render smoothly at any display size. Common formats include svg, pdf and eps. E.g. svg and its source.
  • A vector format scales well to any display size, however, the file size may become prohibitively big when there are many geometric objects (i.e. displaying many data).

Exporting plots

  • To export plots made by ggplot2, use ggsave().
g <- ggplot(cars, aes(speed, dist)) + geom_point()
ggsave(filename = "myplot", 
       dev = "png",
       plot = g,
       width = 6, 
       height = 4,
       units = "in",
       dpi = 300)
  • Unfortunately you may need to adjust the font size when you check the exported plot!

Interactive plots

Interactive plots

  • plotly translates ggplot objects into plotly interactive graphics.
library(plotly)
g <- ggplot(cars, aes(speed, dist)) + geom_point()
ggplotly(g)
  • This doesn’t work well for some (usually complex) type of plots.

Interactive plots with JS through R

  • State-of-the-art for interactive plots is JS
  • No need to learn JS!
  • Many JS library for plotting are available via an R package:
JS R package
Chart.js chartjs, charter
Dygraphs dygraphs
D3.js r2d3, networkD3
ECharts echarts4r
Google Charts googleVis
Highcharts highcharter
Plotly plotly
Vis.js visNetwork
Observable Plot obsplot
Vega and Vega-Lite vegawidget, altair, virgo, vegabrite

3D plots

3D plots

  • ggplot2 is best for static 2D plots
  • For 3D plots, you may like to use some modern interactive tools instead

Resources

For continued learning

Community

Learn with others!

Keep a local copy of the workshop material!

> Download the zip file here
> Open the docs/index.html in a browser