The Global Change Master Directory (GCMD) offers an on-line search and retrieval system for those interested in identifying Earth science data sets for educational and research needs. At the heart of the directory is a database of 3400 Earth science entries.
It includes references to data held at many federal agencies, universities, and foreign countries. Content is updated and software is upgraded continuously by the GCMD staff. Earth science data set descriptions in the GCMD are written in the Directory Interchange Format (DIF). The DIF has gained interagency and international acceptance in documenting directory-level information for the Earth sciences. New fields have recently been added to bring the DIF into compliance with the Federal Geographic Data Committee's Content Standard for Digital Geospatial Metadata. These additional new fields allow more complete documentation for all data sets, including those held in Geographic Information Systems.