A Stronger International Resource for Earth Science Data Discovery
Enhancements to NASA’s Global Change Master Directory (GCMD) create an even more powerful international resource for discovering Earth science data.
Josh Blumenfeld, NASA EOSDIS Science Writer
NASA’s Global Change Master Directory (GCMD) and the docBUILDER online metadata authoring tool were deprecated by NASA’s Earth Science Data and Information System (ESDIS) Project in June 2020. While no changes were made to the directory, all legacy GCMD links now redirect to the Committee on Earth Observation Satellites (CEOS) International Directory Network (IDN).
Since both the GCMD and the IDN were developed using NASA's Earth Observing System Data and Information System (EOSDIS) Common Metadata Repository (CMR) as their foundation, everything that was available through the GCMD is still available through the IDN. The CEOS IDN offers discovery access to the same legacy GCMD datasets using the power of the EOSDIS CMR with the added benefit of access to dataset granules (when available).
GCMD keywords also remain an integral component enabling searches through the directory. The GCMD keywords describe Earth science data and services consistently and comprehensively in a hierarchical format and follow a codified governance process. The power of the keywords is in their ability to enable scientists to tag their data using a taxonomy of controlled scientific categories. This, in turn, allows those searching for data to discover datasets easily through the use of an established hierarchy.
A new tool for contributing metadata to the directory also is available: the draft Metadata Management Tool (dMMT). Users who would like to contribute metadata to the IDN using the dMMT may request access to the tool by emailing firstname.lastname@example.org.
Having the IDN as the primary international directory for Earth science data and related products is a logical continuation of the ongoing evolution of the GCMD.
NASA developed the GCMD in the late 1980s, when metadata was just being recognized as a key component of information systems. The directory was a cornerstone of NASA’s international collaboration and one of NASA’s contributions to CEOS (which designated it the IDN). CEOS was established in 1984 with NASA as a charter member, and includes worldwide space agencies and research organizations that work together to coordinate civilian space observations of Earth and enhance the international exchange of data.
Published July 22, 2020
Updated July 23, 2020
Page Last Updated: Oct 21, 2021 at 1:49 PM EDT