parallel coordinates

Each line is one thing traced across every column. Watch for the line that cuts against the grain — that’s your odd one out.

What it leaves outOnly neighbouring axes can really be compared, so the order you put them in decides which relationships a reader can see.

2 · intermediate · level 3 · compare and choose · taught in dive 3.6

Three worked examples

Five boroughs, four measures. Which one behaves differently?

Before you lookBefore you look at the chart below, write down which borough you expect to stand out, and on which measure.

civictwo_instruments_nyc_rats.csv · 5 rows · 5 columns

rat complaints and rat inspections in the five boroughs of New York

What to look atEach borough is one line crossing four measures. The borough whose line crosses the others is the one where complaints and inspections disagree.

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/two_instruments_nyc_rats.csv.

earth and spacepair_ca_counties_area_population_aqi.csv · 58 rows · 5 columns

every California county's area, population, density and bad-air days

What to look atFifty-eight lines. The ones that stay high across all four measures are the dense, polluted counties — and the crossings are the interesting part.

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.

teen healthnhis_teen_group_profiles.csv · 29 rows · 12 columns

twenty-nine groups of teens across ten measures at once

What to look atEach line is one group crossing every measure. Find the line that goes against the others and name which two measures disagree.

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 → parallel coordinates · two_instruments_nyc_rats.csv