Module 07 Activity

Scenario

Build the chart that will be screenshotted into somebody's slide deck.

What you build

A chart that survives being separated from its report, exported from code.

Steps

1. Write the question the chart answers before choosing a geom, then pick the geom from the question.
2. Describe the mapping first — which column is x, which is y, which is colour — and add layers one at a time, looking after each.
3. If you are comparing groups, try faceting rather than overlaying, and check the number of panels is small enough to read.
4. Set the axis deliberately. Start bar charts at zero, and label any non-zero baseline on a line chart.
5. Write the title as the finding, put units on the axes, and use the caption for the source and the limitation the chart cannot show.
6. Export with ggsave() at a stated size and resolution, then delete it and rebuild it to confirm it is reproducible.

Evidence to hand in

• The question, and the geom you chose for it.
• The chart built up layer by layer.
• The faceted version, if you made one.
• The axis decision and its justification.
• The title, axis labels and caption.
• The exported file, rebuilt from code.

Review checklist

• Every bar chart starts its axis at zero.
• The title states the finding, not the topic.
• Units appear on the axes and the source in the caption.
• Any limitation the bars cannot show is written in the caption.
• The file was exported by ggsave() and regenerated, not screenshotted.

Mark complete