Node-Link Diagram

A visual representation in which discrete entities (nodes) are drawn as shapes such as circles or boxes and relationships between them are drawn as connecting lines or arrows (links/edges). Node-link diagrams are the default visualization for trees, graphs, flowcharts, entity-relationship diagrams, and many data structures, and they convey meaning through both symbolic labels and spatial arrangement. For blind and visually impaired users, node-link diagrams are particularly challenging because the spatial layout carries information (hierarchy, adjacency, direction of flow) that is easily lost when the diagram is flattened into linear ALT text; accessible alternatives include tabular encodings, WAI-ARIA tree navigation, and tactile graphics.