Opportunities for Use of the Spatial Data Transfer Standard at the State and Local Level

Dramatic changes in the way that spatial data have been collected and processed over that last 20 years is leading to a rethinking and restructuring on the most efficient ways to handle geographical information. These changes are taking place at the federal, state, and local governmental levels with great potential for the private sector as well. The formal adoption of the Spatial Data Transfer Standard (SDTS) as the federal database transfer standard for spatial databases signals a new era in this long chain of developments. It offers more flexible and efficient database transfers than earlier tools, and will become the workhorse for implementing the new National Spatial Data Infrastructure. It offers organizations a standard that will make possible and practical a much wider sharing of databases than is currently being done today. Use of the SDTS presents an opportunity to many organizations to share data more easily and reduce the duplication of expensive spatial database resources.     

TIGER/SDTS Topology

The Census Bureau is committed to using the Spatial Data Transfer Standard (SDTS) and is developing an extract from the Census TIGER? called the TIGER/SDTS?. A single file of the prototype TIGER/SDTS is now available with which interested data users may experiment. This paper will graphically describe some of the SDTS concepts and census geographic concepts used in the TIGER/SDTS. The Census TIGER? and the TIGER/SDTS? are trademarks of the Bureau of the Census.     

An SDTS Implementation for GRASS

Developers of the Geographic Resources Analysis Support System (GRASS) at the U.S. Army Corps of Engineering Research Laboratories (USACERL) have been closely involved with the SDTS project since February 1992. Software for the exchange of data between GRASS and SDTS is near completion. Access to SDTS data via this software promises many benefits for GRASS users, but SDTS will also pose challenges to the GRASS user community just as it has for the creation of GRASS-SDTS software itself. Areas of difficulty include distinctions between SDTS and GRASS in the definition of certain spatial objects, SDTS metadata requirements, and accommodation within GRASS of the complex data attribute schemas that will be typical of SDTS data sets.     

Continuing Research Needs Resulting from the SDTS Development Effort

For more than a decade, efforts to develop and specify the U.S. Spatial Data Transfer Standard (SDTS) have on many occasions encountered limitations in both theory and "gaps in our knowledge" which have hindered its development. This work examines broad categories of these limitations from the perspective of research needs, to encourage further research on these topics. Areas in need of further study include fundamental concepts, the specification and use of spatial objects, spatial data quality, entity definitions, the data transfer mechanism, and international comparison of transfer mechanisms. In many cases recent research progress has been made in these areas and this progress is pointed out. A number of high-priority research areas are identified. It is hoped that this work will encourage more research effort to be directed towards these areas, which will benefit not only the development of spatial data transfer standards but also the spatial data sciences in general.     

Implementation of the Spatial Data Transfer Standard in the Commonwealth of Virginia

Present efforts to implement the Spatial Data Transfer Standard (SDTS) within the Commonwealth of Virginia are centered in Virginia's Council on Information Management (CIM). Since 1992, mapping, surveying and land information systems activities have been identified as a responsibility of the Council "The promotion of access to federal and other digital data banks through standards" is an area of CIM interest specified in the Code of Virginia. Prior to adoption of the SDTS by Virginia in November 1994, a Technical Advisory on the SDTS was issued and a SDTS Training and Education Plan was adopted. The Council on Information Management has worked with the USGS SDTS Task Force in developing this plan.