Overview
ISO 19144-2:2023 - Geographic information - Classification systems - Part 2: Land Cover Meta Language (LCML) - defines a standardized UML metamodel (the Land Cover Meta Language) to describe and document land cover classification systems based on physiognomic (physical form) aspects. The LCML provides a common reference structure to compare, map and integrate diverse land cover classification schemes without replacing existing national or thematic systems. The standard supports interoperability, semantic harmonization and robust dataset integration for geographic information and earth observation products.
Key Topics and Requirements
- UML metamodel: LCML is expressed as a UML metamodel with defined object types and relationships for land cover concepts.
- Physiognomic approach: Focus on physical structure (vegetation growth form, surface elements, built-up vs non-built-up surfaces) to enable consistent class definitions.
- Core objects and elements: The metamodel includes structured elements such as LC_Element, LC_VegetationElement, LC_GrowthForm and many subtype/class groupings that capture land cover characteristics.
- Class characteristics and attributes: Mechanisms for expressing class characteristics, name-attribution criteria and numeric value objects to document class rules and thresholds.
- Layering and packages: Supports modular organization of classification components (layers/packages) for flexible representation.
- Conformance and testing: Defines conformance classes (e.g., Class 1 - description of a land cover classification system; Class 2 - comparison of systems) and an abstract test suite (Annex A) for verification.
- Extension and registration: Procedures for extending LCML, registering extensions and ensuring backward compatibility.
- Normative/informative annexes: Includes an abstract test suite (normative) and informative material such as the relationship of LCML to the General Feature Model (ISO 19109) and practical examples.
Applications and Users
- Who uses it: GIS specialists, remote sensing analysts, national mapping agencies, environmental monitoring programs, land-use planners, standards developers, and software vendors.
- Practical uses:
- Harmonizing and comparing different land cover classification schemes for multi-source datasets.
- Enabling semantic mapping and automated translation between class vocabularies.
- Improving interoperability of earth observation products, environmental indicators and land-change analyses.
- Documenting classification rules and metadata for reproducible workflows and data sharing.
- Supporting software implementation of land cover catalogues and conversion tools.
Related Standards
- ISO 19144-1 (Classification systems - Part 1) - related framework for classification systems.
- ISO 19109 (General Feature Model) - LCML’s relationship to the General Feature Model is discussed in informative annex material.
Keywords: ISO 19144-2, LCML, Land Cover Meta Language, land cover classification, UML metamodel, geographic information, data integration, interoperability.