Overview
ISO 19108:2002/Cor 1:2006 is a technical corrigendum to ISO 19108 (Geographic information - Temporal schema). It clarifies and corrects definitions, attributes and operations used to model temporal information in geographic information systems (GIS). The corrigendum updates core terms (for example, edge, feature association, feature attribute, geometric primitive), refines the semantics of temporal primitives (such as TM_Instant, TM_Period, TM_TemporalPosition) and corrects rules for temporal relationships and reference systems.
Key topics and technical requirements
- Definitions and topology
- TM_TopologicalPrimitive: clarified role of 0‑dimensional TM_Node and 1‑dimensional TM_Edge; every topological primitive must belong to exactly one TM_TopologicalComplex.
- Edge defined as a 1‑dimensional topological primitive whose geometric realization is a curve and whose boundary is one or two nodes.
- Feature modeling
- Feature association: relationship linking instances of one feature type to another (or the same) and may be defined as a type or an instance.
- Feature attribute: characteristic of a feature with a name, data type and value domain.
- Temporal primitives and operations
- TM_TemporalPosition: provides the position of a TM_Instant, associated with a single TM_ReferenceSystem; TM_Instant is an identifiable object while TM_TemporalPosition is a data value.
- Relative position operations: corrected return values for relativePosition when comparing TM_Period with TM_Instant, and TM_Period with TM_Period (e.g., Before, After, Contains, Overlaps, Equals, Meets, MetBy). Inputs with indeterminate TM_TemporalPosition must cause an exception.
- timeIndicator: CharacterString default "T" must be included when temporal sequences include units smaller than a day.
- Temporal reference systems and metadata
- domainOfValidity (EX_Extent, ISO/TS 19103) identifies space/time where a TM_ReferenceSystem is applicable and should be used when its valid extent is smaller than the dataset extent.
- Coordinate semantics: coordinateValue holds distance from the scale origin as multiples of the standard interval for the temporal coordinate system.
- Calendar and clock representation: corrigendum replaces Figure 8 (Calendar and clock) to align calendar/clock modeling.
Applications and users
- GIS data modelers and architects implementing spatio‑temporal schemas
- Software vendors and developers building temporal query engines, temporal indexing or time-aware visualization
- Metadata specialists and standards bodies ensuring interoperable temporal reference systems and dataset documentation
- Researchers and practitioners working with time-series, occupancy periods, historical datasets and temporal feature attributes (e.g., TM_Period used as feature attribute subtype)
Related standards
Keywords: ISO 19108, temporal schema, geographic information, TM_Instant, TM_Period, TM_TemporalPosition, TM_TopologicalPrimitive, TM_ReferenceSystem, spatio‑temporal, GIS standards.
