Data Visualization

Charts and graphs are accessibility-hard for several reasons at once. They often rely on colour to distinguish series, encode meaning in shape and size that screen readers can't interpret, and get published as static images with no underlying data. Treating them as structured content, not pictures, is the starting point.

Two W3C user stories show different sides of this. Lexie, an online shopper with deuteranopia and protanopia names pie charts distinguishable only by colour as a daily barrier. Adding a texture or label alongside colour fixes it without changing anything for anyone else. Lakshmi, who is blind, needs the underlying data as a table or structured text description. A screen reader can't interpret a pixel-rendered chart.

Don't rely on colour alone: pair it with labels, patterns, or direct numeric values. Make the underlying data available as a table. Write a text description that explains what the chart shows, not just its title. And make sure charts scale without breaking when zoomed.