ISO 19118:2011

Overview

ISO 19118:2011 - Geographic information - Encoding defines requirements for creating encoding rules used to interchange geographic information across systems. Part of the ISO 19100 series, it specifies how application schemas (typically modelled in UML) are turned into system‑independent data structures suitable for storage and transport. The standard covers requirements for UML‑based encoding rules, encoding services, and an XML‑based encoding rule intended for neutral data interchange. It does not prescribe digital media, transfer protocols, or inline large image encoding.

Key topics and technical requirements

• Encoding rules: Defines what an encoding rule must specify - types of data, syntax, structure and coding schemes for the output data structure.
• UML schemas and instance models: Requirements for mapping UML application schemas to a generic instance model used for interchange.
• Conversion rules: Guidance on converting input instances and/or schemas into the output data structure (instance conversion and schema conversion).
• Encoding services: Requirements for software components that implement encoding rules (encode, decode, generate output schema). Conformance classes cover generic services and services that encode, decode, or produce schemas.
• Character repertoire and data types: Use of ISO/IEC 10646 (UCS) and conformance with standards like ISO 8601 for dates/times.
• Conformance and testing: Abstract test suites (Annex B) define test cases for encoding rules and encoding services.
• XML-based rule (Annex A): Normative requirements for an XML encoding profile intended for neutral interchange; Annex C gives informative examples of community use.

Applications and users

ISO 19118:2011 is directly applicable to:

• GIS software developers and library implementers building encoding services for reading/writing geospatial data.
• Standards architects and data stewards designing application schemas and interoperability workflows.
• System integrators, national mapping agencies, and data providers exchanging geospatial datasets across platforms.
• Organizations needing a neutral, standards‑based XML encoding to ensure long‑term interoperability and machine‑readable interchange.

Practical uses include creating platform‑neutral exports/imports of geospatial datasets, defining conversion chains between schema versions, and validating encoding implementations against the abstract test suite for conformance.

Related standards

• ISO 19100 series (overall framework)
• ISO 19101 (fundamental concepts)
• ISO/TS 19103 (conceptual schema language)
• ISO 19109 (rules for application schema)
• ISO/IEC 10646 (UCS character set)
• ISO 8601 (date/time) and W3C XML 1.0

Keywords: ISO 19118:2011, geographic information, encoding, encoding rules, XML-based encoding, UML schemas, encoding services, geospatial interoperability, data interchange.