Rules that define and enforce the spatial relationships between geographic features, such as no gaps between polygons, no overlapping lines, or points must fall within polygons.
Topology ensures that a spatial dataset is geometrically consistent. Without topological rules, a dataset of municipal boundaries might have tiny gaps between adjacent municipalities, or two road segments might not connect properly at an intersection. These errors cause problems in spatial analysis and routing.
Topological rules are enforced during data creation and editing. Common rules include: polygons must not overlap, polygons must not have gaps, lines must connect at endpoints, and points must be covered by polygons.
Example: A dataset of land parcels should have no gaps or overlaps — every point on the ground should belong to exactly one parcel. A topology check identifies any parcels that overlap or leave unclaimed gaps, which are then corrected before the dataset is published.