The Global Change Master Directory (GCMD) holds information that allows searchers to find useful Earth science data sets. More than 1000 EOS (Earth Observing System) data sets and about 7000 other data sets from federal agencies, universities, research institutes, and international organizations are described in the Directory. The directory is available at: http://gcmd.nasa.gov. The site attracts about 20,000 users per month.

A hierarchical keyword interface was designated as the primary search option (the "default" interface). The science keyword search normalizes the search for data because every data set description carries the earth science keywords that describe the contents. Keyword definitions are available on-line during searches.

One of the services offered is the Subscription Service which allows users to specify their data interests. When data sets fitting the user’s parameters are added to the database, data set descriptions are automatically e-mailed to requestors without them having to search repeatedly.

A Global Change Conference Calendar is also available which holds hundreds of links to upcoming conferences, along with an archive of past conferences. An experimental Learning Center has been added to respond to common earth science questions received through the user support office. The Learning Center is showing increased activity as part of educational outreach efforts. "Ask Dr. Global Change" questions are fielded by the U.S. Global Change Research Program information office.

A customized free-text search interface has been developed to allow partners to maintain identity and intellectual ownership. Interfaces have been established with partners such as the U.S. Department of Agriculture, the Earth Science Information Partners federation, and the Antarctic Master Directory. Other interfaces are being developed with partners such as the Global Observing System in progress.

The front page of this side is simple to understand and the major categories of data are listed clearly. Some of the data available include land use, vegetation, water, geology, geothermal, and much much more. Besides the extensive amount of data available, the FAQ sections are well done and you can find out nearly everything you need to know about Global Change.

This article is reprinted from Earth Science Computer Applications Monthly Newsletter. Click to the Web site for more information about the newsletter and other Gibbs Associates publications.