the rose

Each wedge points a direction, and its length is how many landed that way. There’s no left-to-right, so don’t read it as a trend.

What it leaves outArea grows faster than length, so a wedge twice as long looks four times as big. The eye reads the area.

2 · intermediate · polar · level 2 · ask who counted · taught in no dive yet

Two worked examples

Seven days, bent into a circle. Is there a trend?

Before you lookWrite down whether you expect earthquakes to prefer a day of the week.

civicweekday_nyc_rat_complaints.csv · 7 rows · 2 columns

rat complaints by day of the week, bent into a circle

What to look atWedge length is the count for that day. There is no left-to-right, so there is no trend — only which directions are long.

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/weekday_nyc_rat_complaints.csv.

earth and spacerose_quakes_by_direction.csv · 8 rows · 2 columns

a year of southern California earthquakes, by the direction they came from

What to look atSouthwest 46, northwest 801 — seventeen times as many, and the circle is the right shape for it because a compass has no left-to-right either. Now read the long wedge again: 507 of those 801 name one place, Grapevine. One swarm can own a rose.

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/rose_quakes_by_direction.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 rose · weekday_nyc_rat_complaints.csv