NASA's Global Change Master Directory (GCMD) holds Earth science data set and service descriptions, which cover subject areas within the Earth and environmental sciences. The project mission is to assist researchers, policy makers, and the public in the discovery of and access to data, related services, and ancillary information (which includes descriptions of instruments and platforms) relevant to global change and Earth science research. Within this mission, the directory also offers online authoring tools to providers of data and services, facilitating the capability to make their products available to the Earth science community.
The GCMD evolved from the prototype NASA Master Directory (NMD) as part of the National Space Science Data Center (NSSDC) at NASA/Goddard Space Flight Center to promote the exchange of scientific data sets through the Catalog Interoperability (CI) project. In the summer of 1987, the CI Working Group (consisting of several U.S. Federal and international agencies) defined the type of information and level of detail that would be contained within the NMD. The first version of the NMD was released during that year. In 1989, the Committee on Earth Observation Satellites (CEOS) Data Working Group (DWG) established the CEOS International Directory Network (IDN) to foster the exchange of information among international agencies. In 1990, the Interagency Working Group on Data Management for Global Change (IWGDMGC) adopted the directory as a prototype to facilitate global change research - in response to the challenge by the Earth System Science Committee (ESSC). Thereafter, the NMD was renamed the Global Change Master Directory (GCMD) for its Earth sciences applications. In 1994, the GCMD project became part of the Global Change Data Center within the Earth Sciences Directorate at NASA/GSFC, where it still resides.