Visualizing global debt across the last decade
A circular timeline poster that makes ten years of government debt readable at a glance.
Overview
General government debt-to-GDP measures a government’s gross debt as a percentage of GDP, and it is a key indicator of whether public finances are sustainable. I designed a circular timeline chart that puts a decade of that OECD data (2013–2022) for 40 countries on one poster, and I handcrafted every stroke of it in Adobe Illustrator.
The problem
The data comes from the OECD as a table of countries by year. Stretched across a long period of time, it is difficult to visualize.
The chart and map views on the OECD site show the data, but over a decade they are hard to read, which makes it difficult to notice trends or the factors behind a change.
Original dataset from the OECD
Chart view on OECD
Map view on OECD
Process
I set up a polar grid in Illustrator and anchored every stroke by hand. I had to digitally handcraft each stroke and its spacing, which took up to 17 hours of work.
Color was the other hard part. I tried using ChatGPT to find colors that contrast well, but it was extremely limiting. Many of the 40 countries end up with similar colors, so I placed them strategically, with neighboring colors guiding where each one goes.
Anchoring strokes on a polar grid in Illustrator
The color list ChatGPT gave me
The solution
A decade of data in a circular timeline chart. Each uniquely colored segment represents a country, and the length of each stroke shows debt as a percentage of GDP, from 10% to 200%, across 2013–2022.
Two circles, 100% vs 200%
Two large circles make the difference between 100% and 200% debt-to-GDP clear at a glance.
A labeled index
A section of the circles is labeled with percentages, so readers know how to read the index.
Color coded, with arrows to guide the flow
Each country is color coded in fine detail, and simple arrows guide the order the countries are shown in. Similar colors do appear across the index, but they are placed strategically, with neighboring colors guiding their placement.
Results & learnings
The finished poster is 80 × 160 in and uses 20 colors, with the whole decade readable in a single view. Zoom in and you can see, and count, each stroke that was carefully crafted.
Two things I learned: handcrafting every stroke and its spacing took up to 17 hours, and ChatGPT was extremely limiting when I needed colors that contrast well.
