Data visualization accessibility

The practice of making charts, graphs, maps, dashboards, and other visual representations of data perceivable and understandable by people with disabilities, particularly screen-reader users and people with colour vision deficiencies. Most web-based visualizations are rendered as SVG or HTML canvas elements that are semantically opaque to assistive technologies — a screen reader encounters only an empty image unless explicit accessibility measures are taken. Approaches to accessible data visualization include providing text summaries of key trends and patterns, adding appropriate ARIA roles and labels to chart elements, supporting keyboard navigation through data points, using sonification to represent data as audio patterns, offering voice-based query interfaces for exploring data, and ensuring sufficient colour contrast and non-colour-based encoding for colour-blind users. WCAG provides general guidance but lacks visualization-specific criteria, making this an area where practitioners must go beyond minimum compliance.