DIF (Directory Interchange Format)

From Federation of Earth Science Information Partners

What

DIF is an early metadata initiative from the Earth sciences community, intended for the description of scientific data sets. It includes elements focusing on instruments that capture data, temporal and spatial characteristics of the data, and projects with which the dataset is associated.


Who

DIF supports data discovery in NASA's Global Change Master Directory (GCMD).


Objective

To serve as the "container" for the metadata elements that are maintained in the International Directory Network (IDN) database, where validation for mandatory fields, keywords, personnel, etc. takes place. A DIF consists of a collection of fields which detail specific information about the data. Thus, it allows users to understand the contents of a data set and determine whether a particular data set would be useful for their needs.


Notes

The DIF structure has been flexible enough to evolve with growing metadata requirements, especially for the geospatial disciplines. In the U.S., the Office of Management and Budget's (OMB's) Circular A-16 for the improved coordination of spatial data among federal agencies led to the establishment of the Federal Geographic Data Committee (FGDC) and the FGDC Clearinghouse. The GCMD serves as NASA's FGDC Clearinghouse node for geospatial metadata. Elements of the Content Standard for Digital Geospatial Metadata (CSDGM) were incorporated in the DIF in 1994. DIF is fully compatible with the ISO 19115/TC211 geospatial metadata standard and is defined as a W3C XML* Schema.


*XML (Extensible Markup Language) defines a set of rules for encoding documents in a format which is both human-readable and machine-readable. Although the design of XML focuses on documents, it is widely used for representation of arbitrary data structures - such as those used in web services.


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