Understanding ISO 19115 – The Geographic Metadata Standard

What is ISO 19115? — Overview of the Standard

ISO 19115 is the international standard for documenting geographic information and services. It functions as a universal language for metadata—the “data about data”—offering a structured way to describe datasets like maps or satellite imagery. This documentation answers critical questions, such as:

• Who created the data?

• What area does it cover?

• How accurate is it?

• When was it last updated?

The standard’s primary goal is to ensure consistency and interoperability. Without such a common framework, organizations would use countless methods to describe their data, making it nearly impossible to discover, evaluate, or combine information from various sources. By establishing a standardized set of rules, ISO 19115 solves this problem, ensuring that a dataset from one organization can be correctly understood and used by another—fostering collaboration and preventing data silos.

To achieve this, the standard provides a comprehensive schema with detailed terms, definitions, and required elements. It outlines which data properties must be recorded—from basic identification details (title, abstract) to complex technical information (data quality, spatial reference systems, and distribution formats).

ISO 19115–1:2014 — Metadata Schema Explained

ISO 19115-1:2014, subtitled ‘Fundamentals,’ is the foundation of the standard. It translates the abstract concept of standardized documentation into a concrete schema, defining the framework and rules for creating consistent, interoperable metadata for geographic information and services.

This schema organizes metadata into logical categories to document every critical property of a dataset. Key documented aspects include:

• Identification: Title, abstract

• Extent: Geographic and temporal coverage

• Quality: Accuracy, lineage

• Content: Description of the data’s content

• Spatial Reference System: The coordinate system used

• Distribution: Access formats and contact information

This systematic approach ensures users have a clear understanding of the data’s characteristics and usability.

Key Metadata Elements — What You Need to Know

A key feature of the ISO 19115 schema is its structured flexibility. It achieves this by categorizing elements into three main types, balancing simplicity with comprehensiveness:

• Mandatory: Required for all datasets.

• Conditional: Required only if specific characteristics apply.

• Optional: Used to provide richer, more detailed descriptions.

This design ensures a baseline level of information is always present while allowing for more detailed documentation when needed.

These element types apply across all core information categories. For instance, a dataset’s title (identification) is mandatory, whereas detailed lineage information (data quality) might be optional. The framework also includes a method for extending the schema, allowing organizations to add custom elements for specialized needs without compromising core interoperability.

ISO 19115–2:2009 — Extensions for Imagery and Gridded Data

While the core ISO 19115 standard provides a strong framework for general geographic data, the unique characteristics of imagery and gridded data demanded a more specialized approach. This need prompted the development of ISO 19115-2:2009, an extension designed specifically to describe remotely sensed datasets. It complements the core standard by adding metadata elements that describe the specifics of data collected from sensors, such as those on satellites or aircraft.

This extension introduces fields for documenting crucial acquisition and processing details, including:

• Acquisition Platform: The satellite or aircraft used.

• Instrument: The specific sensor that collected the data.

• Collection Parameters: Physical details of the data collection process.

• Processing Level: The stage of processing the imagery has undergone.

• Grid Properties: Cell geometry and orientation for gridded data.

By providing these specialized elements, ISO 19115-2:2009 greatly improves metadata completeness for imagery and gridded datasets. This detailed documentation improves data discovery and evaluation, allowing users to assess a dataset’s suitability for their work without inspecting the raw data.

Implementing ISO 19115 — Guidelines and Best Practices

Successfully implementing ISO 19115 is about more than just filling out fields; it requires a systematic approach guided by best practices. The goal is to create consistent, high-quality metadata that allows users to confidently assess a dataset’s fitness for their needs, thereby improving data quality and usability.

Organizations like NASA have developed detailed implementation guidelines that provide an excellent blueprint. A successful strategy requires thoroughly documenting key aspects of the data, including:

• Clear identification information

• Defined spatial and temporal extent

• Assessed data quality

• Outlined distribution details

Focusing on these core elements builds a robust foundation for data standardization and integration.

Using specialized tools is essential to simplify this process and ensure compliance. Metadata editors and repositories, for instance, are designed to help with the creation and management of ISO 19115-compliant records, often providing templates and validation checks to minimize errors.

Metadata Tools — Supporting ISO Standards

Powerful software tools exist to simplify the creation of compliant metadata. For example, popular editors and repositories like NASA’s Common Metadata Repository (CMR) and ESR’s ArcGIS Pro are specifically designed to help create, edit, and manage of metadata that adheres to the ISO 19115 standard.

These platforms simplify metadata generation by offering both pre-built templates and automated validation features. The templates guide users through the necessary fields to ensure all mandatory elements are included, while validation checks entries against the official ISO 19115 schemas. This dual functionality not only saves time but also greatly improves consistency and guarantees interoperability between different datasets and systems.

Updates and Amendments — Keeping ISO 19115 Relevant

The field of geographic information is dynamic, so any effective standard must also evolve. Consequently, ISO 19115 is a living document, regularly updated through amendments to address the changing needs of the geospatial community and provide a strong framework for modern datasets.

These updates often introduce significant enhancements, such as amendments to ISO 19115-2 that expanded its capabilities for describing imagery and gridded data. For instance, a key 2020 amendment (A1) improved components for describing data quality. By adapting to new technologies, these revisions enhance metadata completeness and ensure continued interoperability.

Conclusion — The Importance of ISO 19115 in Geographic Data

Geographic data is only as valuable as our ability to find, understand, and trust it, and ISO 19115 is the key standard that makes this possible. It achieves this by providing a structured language to describe the critical aspects of a dataset, including:

• Identification

• Spatial extent

• Data quality

• Distribution

• Lineage

This creates a clear, consistent, and universally understood record for all geographic information.

The standard’s main benefit is fostering interoperability and collaboration. By adhering to ISO 19115, organizations ensure their datasets can be easily discovered, evaluated, and integrated by others, breaking down data silos and maximizing the return on investment in data collection.