ISO 19115: Geographic Information - Metadata is becoming one of the more widely-accepted protocols for documenting geospatial data, and is probably the best option for data producers working in the international domain. In 2010, the United States Federal Geographic Data Committee (FGDC) officially endorsed the ISO suite of standards, known as the ISO 191** series, for federal use and development. The older FGDC Content Standard for Digital Geospatial Metadata (FGDC-CSDGM) has since been designated a legacy standard that will be continue to be supported in the future, however there is a growing emphasis in federal data production and stewardship to adopt tools and workflows to support the implementation of the ISO standard.
ISO 19115 is a content standard. As such, it prescribes the information and relationships that should be captured to describe a geospatial resource, but it does not specify how the standard ought to be implemented. The file type conventionally used to create and exchange ISO 19115 metadata records is an eXtensible Markup Language (XML) file. Workflows for creating, editing, and validating ISO 19115 records generally employ software that can read and write XML files, as well as 'validate' the XML files against the schema defined in ISO 19139: Geographic Information Metadata XML Schema Implementation.
Metadata authors and managers should understand that the Alaska Data Integration Working Group (ADIwg) metadata standard differs from the ISO 19115 in content and structure. The ADIwg metadata standard is an independent metadata standard that describes a slightly different set of informational pieces and relationships (or metadata 'elements') and uses a different file format for creating and storing metadata. Rather than using a relational database or the XML files common in the ISO workflow, ADIwg metadata records are written in and stored as Java Script Object Notation (JSON) files. Metadata validation for ADIwg records is analagous to ISO 19115 metadata validation, however a JSON schema is used instead of the ISO 19139 XSD schema. In the same way that ISO 19115 files must be compliant with ISO 19139, the published XML standard, ADIwg JSON files must conform to the ADIwg JSON schema to be valid.
While the file format, element names, and structural organization differ between ADIwg JSON metadata records and ISO 19115 XML metadata records, both standards seek to capture the same fundamental information about a data product. This critical information generally includes the details about the data itself, the organization or individuals that created it, related products or resources connected to the data, access and/or use limitations, and any specific information about how to properly interpret and use the data.
Although the way these different components are stored may differ between the two formats (e.g., the general description of a data resource may populated in Element 'X' in an ISO 19115 XML file, while the same information may be stored in Element 'Y' in an ADIwg JSON file), most of the elements in an ISO metadata record have corresponding elements in the ADIwg JSON standard. To this end, it should be possible to translate or crosswalk most ISO 19115 metadata records into the ADIwg standard. Users familiar with the ISO standard who wish to generate new records from scratch in the ADIwg format should be able to represent the same information they would have collected in an ISO XML file using the corresponding elements in the ADIwg JSON file.