Coverage

A coverage is a digital map data structure used in the ARC/INFO geographic information system to store and manage vector-based spatial data. It organizes geographic information into a structured format that represents real-world features in a precise and analyzable way. In a coverage, spatial features are stored as arcs (lines), nodes (endpoints and intersections), polygons (areas), and label points (feature identifiers placed within polygons). Together, these elements define the geometry and location of geographic entities such as roads, rivers, land parcels, or administrative boundaries.

A key characteristic of a coverage is that it maintains topological relationships between features. This means it records how features connect, share boundaries, and relate to one another—for example, which arcs form a polygon or which nodes connect multiple arcs. This topology ensures data integrity, reduces spatial errors, and supports advanced geographic analysis such as network tracing, overlay operations, and adjacency studies.

Coverages typically represent a single thematic dataset, such as transportation networks, hydrography, soils, elevation zones, or land use. Each coverage is associated with attribute tables that store descriptive information about the spatial features, enabling users to link geographic shapes with real-world properties.