Overview
SIST EN ISO 19148:2021 - Geographic information - Linear referencing (ISO 19148:2021) specifies a conceptual schema for representing locations measured along one-dimensional objects (for example, road centerlines, pipelines, rails) and optionally offset from them. The standard defines the data structures, expressions and operations needed to create, store, exchange and process linear referencing information. It updates and supersedes the 2012 edition and is adopted as a European (EN) and Slovene (SIST) standard.
Keywords: ISO 19148:2021, linear referencing, geographic information, linear georeferencing, linear referencing system.
Key technical topics and requirements
- Conceptual schema for linear referencing: position expressions, distance expressions and value expressions describing location along a linear element.
- Linear elements and types: concepts for LinearElement, LinearElementType and interfaces (e.g., ILinearElement, IFeature, ISpatial) used to reference one-dimensional objects.
- Linear Referencing Methods (LRMs): mechanisms to represent positions along an element (including direction, offset and towards-referent conventions).
- Offset support: lateral and vertical offset models, vector offsets and cross‑sectional conventions to represent positions displaced from the linear feature.
- Linearly located events and segmentation: event modelling (Event, AttributeEvent, FeatureEvent), location types (AtLocation, FromToLocation), and segmentation classes (SegmentableFeature, LinearSegmentSet) to manage events and partitions along linear networks.
- Conformance and testing: conformance classes for data types and operations, normative abstract test suite (Annex A) to validate implementations.
- Documentation and examples: informative annexes provide a generalized model, common methods, application schema examples, event/segmentation examples and notes on backwards compatibility with ISO 19148:2012.
Practical applications and who uses it
ISO 19148:2021 is applicable across domains that require precise, repeatable location referencing along linear assets:
- Transportation agencies: road inventories, roadworks, signage, incident mapping and asset management.
- Utilities and pipeline operators: linear asset inspection, maintenance scheduling and leak/event reporting along pipelines or cables.
- Rail and transit: track geometry, signals and event logging referenced to track chainage.
- Environmental monitoring: sampling, riparian surveys and impact assessments tied to river reaches or coastlines.
- Location-based services & GIS vendors: routing, geocoding, map data exchange and application interoperability.
Users: GIS architects, data modelers, software developers, asset managers, standards bodies and system integrators implementing linear referencing in enterprise GIS and location-based applications.
Related standards and resources
- Prepared under ISO/TC 211 (Geographic information/Geomatics); aligns with the ISO 19100 series of geographic information standards.
- Annexes in ISO 19148:2021 provide test suites, example application schemas and migration guidance from the 2012 edition to aid implementation.
