the dotplot

One dot per thing, stacked where they land. Between a picture graph and a histogram.

What it leaves outAbove a few hundred values the dots run out of room and start to overlap, so the stack stops being an honest count.

2 · intermediate · cartesian · rung 2 · what’s reported

GAISE II · Level A p.23, Level B p.45 · shipped on the platform · specBuilder.ts · buildDotplotSpec -- rank-window transform

Three worked examples

How many days were like today?

Before you lookWrite down roughly how many service requests you think a normal day brings.

civichist_la_311_per_day.csv · 365 rows · 2 columns

how many service requests came in on each of 365 days

What to look atOne dot per day, stacked where they land. You can count the dots in a stack — that is what a histogram takes away from you.

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/hist_la_311_per_day.csv.

earth and spacenoise_socal_m4_by_year.csv · 30 rows · 2 columns

how many magnitude-4-or-greater quakes happened each year for thirty years

What to look atThirty dots. Small enough to count, which is exactly when a dotplot beats everything else.

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/noise_socal_m4_by_year.csv.

teen healthnhis_teen_estimates.csv · 1,700 rows · 9 columns · showing 400 of 1,700 rows on this page; the file has all of them

every published estimate, one dot each

What to look atMost estimates land between 10 and 70 per cent. The dots at the far ends are the ones worth opening the table for.

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_estimates.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 dotplot · hist_la_311_per_day.csv