Charts using icons or shapes to represent a quantity.
Chris Love at The Information Lab provided this blog post:
Emily Chen at the Data School shared this great post. Whilst I couldn’t find any videos of this chart type being constructed, Emily’s post goes include a brief .gif file or two:
Ryan Sleeper has also written about this chart type:
Andy Kriebel shares how to create unit charts in tooltips, written by his guest poster Rody Zakovich:
This from Andy Kriebel is arguably a form of unit chart / dot plot (at least in my head it is!):
A more conventional interpretation is this, by Chris Love (taken from his blog post):