the bubble chart

Compare things on three or four measures at once — position, colour and size all carry one.

What it leaves outSize is the weakest channel on the chart. A bubble twice the area does not look twice as big, and small ones vanish under large ones.

4 · data science · cartesian · rung 4 · what isn’t there

shipped on the platform · circle + size channel -- no shape yet

Three worked examples

Position, colour and size. How many can you read at once?

Before you lookWrite down how many things you think you can track on one chart.

civicpair_ca_counties_area_population_aqi.csv · 58 rows · 5 columns

California counties: density, bad-air days, population and area

What to look atPosition, size and colour each carry one measure. Three at once is useful; four is usually one too many.

This example draws itself with a small script. With scripting off you can still read every word on this page, and the file itself is at data/pair_ca_counties_area_population_aqi.csv.

earth and spaceabsence_ca_counties_air_monitoring.csv · 58 rows · 5 columns

counties by population, land area and median air quality

What to look atSize the bubbles by population and the empty counties shrink out of sight — which is exactly the thing this dataset is about.

This example draws itself with a small script. With scripting off you can still read every word on this page, and the file itself is at data/absence_ca_counties_air_monitoring.csv.

teen healthnhis_teen_group_profiles.csv · 29 rows · 12 columns

the same groups, now with more measures on the same chart

What to look atRead the position first, then the size. Add the third channel and ask honestly whether you are still reading all of them.

This example draws itself with a small script. With scripting off you can still read every word on this page, and the file itself is at data/nhis_teen_group_profiles.csv.

the pool

Now build one yourself.

The pool opens with this file and this shape already drawn, so your first move is to change something rather than to start from nothing. Bring your own CSV if you have one. Nothing is uploaded anywhere — the chart is drawn in your browser, your work saves there, and it downloads as a picture or as a project file you can open again.

Open the pool → the bubble chart · pair_ca_counties_area_population_aqi.csv