Introduction

The Framework Data Standard establishes common requirements for data exchange for seven themes of geospatial data that are of critical importance to the National Spatial Data Infrastructure (NSDI), as they are fundamental to many different Geographic Information Systems (GIS) applications. These themes are known as NSDI framework themes. The seven NSDI Framework Themes and coordinating Federal Agencies are:

1. Cadastral data, DOI - BLM
2. Digital orthoimagery, DOI - USGS
3. Elevation, DOI - USGS
4. Geodetic control, DOC - NGS
5. Government Units, DOC - Census Bureau
6. Hydrography, DOI - USGS
7. Transportation (Roads), DOT - BTS

Framework data standards specify a minimal level of data content that data producers, consumers, and vendors are expected to use for the interchange of framework data, including through Web services.

Each of the framework data standards includes an integrated application schema expressed in Unified Modeling Language (UML) developed through the Object Management Group (OMG). The application schema specifies, as appropriate, the feature types, attribute types, attribute domain, feature relationships, spatial representation, data organization, and metadata that define the information content of a data set. For the exchange of UML models between various modeling software packages, XML Metadata Interchange (XMI) format files are made available (XMI is another specification developed by OMG).

While the framework data standards do not specify a single structure for the interchange of data, an implementation using the Geography Markup Language (GML) Version 3.1 developed through the Open Geospatial Consortium, Inc. (OGC) has been created. Both simple and full expressions of GML are available.

The draft framework data standards were initially developed through the Geospatial One-Stop e-Government initiative; however, the FGDC has assumed leadership for continued standards activities.

The American National Standards Institute (ANSI) has accredited the InterNational Committee for Information Technology Standards (INCITS) as a standards development organization working under ANSI rules. The Framework Data Standard will go through the ANSI/INCITS standards process in order to secure broad non-Federal participation in their development and to take advantage of the technical expertise in ISO and ANSI standards that members of INCITS Technical Committee L1, Geographic Information Systems, can provide. This is in compliance with OMB Circular A-119, which directs Federal agencies to use voluntary consensus standards such as ANSI standards.

It is expected that this approach will result in standards that meet the basic needs of all sectors and that are widely implemented in government and business and through vendor tools and technologies.