Overview
ISO 19152-4:2025 - Geographic information - Land Administration Domain Model (LADM) - Part 4: Valuation information extends the LADM family to cover the valuation aspects of land administration. It provides an abstract, conceptual model for representing property values, valuation processes, transaction prices and sales statistics, and valuation units (parcels, buildings, condominium units and valuation unit groups). The standard is encoding‑neutral and designed to be the basis for national, regional or local profiles and interoperable valuation services. It builds on ISO 19152-1 and ISO 19152-2 and explicitly does not override national valuation regulations.
Key Topics and Technical Requirements
- Conceptual model: Defines classes and associations for valuation information, including VM_ValuationUnit, VM_ValuationUnitGroup, VM_SpatialUnit, VM_Building, VM_CondominiumUnit, VM_Valuation, VM_MassAppraisal, VM_TransactionPrice, VM_SalesStatistic and VM_ValuationSource.
- Values covered: Assessed values, valuation procedures, mass valuation (mass appraisal), transaction prices and derived sales statistics.
- Versioning & conformance: Uses a VersionedObject approach for lifecycle management; conformance rules and an abstract test suite are specified (Clause 4 and Annex A).
- Encoding independence: Content model is independent of any specific encoding (XML, JSON, GML, etc.), enabling model‑driven architecture (MDA) implementations and mapping to local data formats.
- Interoperability & semantics: Provides a simplified common terminology to describe diverse national and informal valuation practices, enabling coherent aggregation and exchange of valuation data from multiple sources.
- Spatial analysis support: Includes guidance and profiles for 2D/3D spatial analyses relevant to valuation (Annex B).
- Supporting artifacts: Instance examples (Annex C), links to international valuation guidance (Annex D), treatment of unregistered land (Annex E), code lists (Annex F), country profiles (Annex G) and mapping to International Property Measurement Standards (Annex H).
Applications and Who Uses It
ISO 19152-4:2025 is practical for:
- National and local authorities: cadastral agencies, land registries, tax and valuation authorities seeking consistent valuation data models.
- GIS and software vendors: developers building valuation, tax, cadastre or property information systems and services.
- Consultants and surveyors: implementing mass appraisal systems, valuations for compensation, land readjustment and public value capture.
- Data integrators and researchers: combining transaction, sales statistics and assessed value datasets across jurisdictions.
Use cases include property taxation, compensation on expropriation, mass appraisal workflows, real estate market analysis and integration of valuation with cadastral and permitting registries.
Related Standards
- ISO 19152-1 and ISO 19152-2 (LADM core)
- ISO 19131 (data product specification - noted as out of scope for this conceptual model)
- Cadastre 2014 (FIG conceptual framework)
- International Valuation Standards, IAAO technical standards and International Property Measurement Standards (IPMS) - referenced for alignment and best practice.