Directory Interchange Format (DIF) Standard

Summary

This document defines the Directory Interchange Format (DIF) content metadata, a specific set of attributes for describing Earth science data. From its conception in the late 1980’s as a way to document and exchange information on scientific data to its implementation in the Global Change Master Directory (GCMD), the DIF has evolved to serve the user community in the discovery, access and use of Earth science and related data.

Status

The Directory Interchange Format (DIF) Standard is an approved standard recommended for use in NASA Earth Science Data Systems in September 2008.

Specification Document

Directory Interchange Format (DIF) Standard

User Resources

Updates to GCMD Directory Interchange Format (DIF)

docBUILDER (GCMD tool for writing DIFs)

NASA Earth Science Community Recommendations for Use

Strengths

The DIF is a mature specification. It was first developed in 1987, was chosen by the CEOS IDN (Committee on Earth Observation Satellites International Directory Network), and has been used by the NASA GCMD (Global Change Master Directory) as the means of metadata exchange. The DIF continues to be actively used and maintained by a large variety of organizations, both as a means of interaction with the GCMD as well as for other purposes, including internal data management. The DIF metadata model is compatible with the ISO 19115 metadata model.

Weaknesses

While the DIF is compatible with ISO 19115, there is a feeling among some metadata providers that the DIF should be superseded by ISO 19115.

Applicability

The DIF is meant to contain collection level metadata for Earth science data sets. It is not designed for use as granule, or inventory level metadata. The DIF is primarily a metadata interchange format. Data holders often manage metadata in different internal formats, choosing to export and import metadata in DIF format when interchanging metadata with external organizations, primarily the GCMD.

Limitations

Since DIF is not suited directly as an inventory level metadata format, some data holders perceive this as a limitation. They would prefer to be able to use the same format for inventory level data.

Overall, the DIF is a widely implemented and widely deployed specification that provides a standard way of storing and exchanging Earth science metadata. The ESDS-RFC-012 TWG thus recommends its endorsement by the SPG as an Earth Science Data Systems Standard.

Page Last Updated: May 3, 2019 at 10:00 AM EDT