Supporting the National Spatial Data Infrastructure at the United States Census Bureau

Abstract
The United States Census Bureau built its national geospatial digital data base, the T opologically I ntegrated G eographic ncoding and R eferencing (TIGER)System, during the 1980 ’ s to support the 1990 Decennial Census of Population and Housing.The TIGER data base is a seamless digital map of the United States in the public domain.Not only did it spawn the multibillion dollar Geographic Information Systems (GIS)industry that exists in the United States today,but perhaps more importantly,it provided a solid foundation for the United States National Spatial Data Infrastructure (NSDI)and a model for the NSDI vision.

Background
The proliferation of geospatial digital data in the United States (US)exploded in the early 1990 ’ s.Numerous federal agencies were building geospatial data sets,many times duplicating information already in existence or being created elsewhere in the country. The U.S.Office of Management and Budget (OMB)issued a document,Circular A-16, mandating that all U.S.federal agencies coordinate the development and maintenance of their geospatial data sets according to specific guidelines.The OMB established the Federal Geographic Data Committee (FGDC)to coordinate activities across the federal community to ensure the five basic tenets of A-16 would be met by all federal agencies creating geospatial data.The five key components for the US NSDI are:

Determine the data themes of common national significance and coverage,which has become known as “ Framework Data “
Establish a National Spatial Data Clearinghouse
Define standards and metadata
Ensure federal activities are in support of the NSDI
Establish partnerships for data development and stewardship

All U.S.federal agencies must comply with the terms of Circular A-16 in order to receive funding for mapping and data base development activities.

When the FGDC was first established,only federal agencies were involved in defining the data themes for the Framework Data.The federal agencies had set ideas of what content and standards were necessary to support national programs.State,local,and tribal governments across the United States had their own notions as to how this should be accomplished and forced their way to the table.As federal agencies were looking to state, local,and tribal governments to assist in updating and populating the national data sets, their input and cooperation was vitally necessary.

The TIGER/Line . files – the public version of the internally formatted TIGER data base --were a great success when the U.S.Census Bureau first released them to the public in 1989.Many state,local,and tribal partners quickly adopted the TIGER/Line . files as the foundation of new GIS systems to support their jurisdictions.The fact that TIGER data are in the public domain made its use the logical starting point for any local or tribal government entering the GIS arena.Users immediately began improving the geopositional accuracy of the coordinates and updating the network and attribute data as soon as TIGER information was loaded into their GISs.A natural progression in the maintenance of the TIGER data base was that state,local,and tribal partners using the data and improving it wanted to feed to the Census Bureau their corrections and improvements.They became stakeholders in the TIGER data base,its content,and its future.

With all that was invested in updating and maintaining their coverage of the data,they insisted they be included in the processes defining standards and metadata.This was true of their relationships with a number of federal agencies.One of the most compelling factors that finally got nonfederal stakeholders to the table for defining the framework layers was the fact that,in many cases,the federal agencies were depending on them to assist in maintaining and updating the data for their jurisdiction.Unfortunately,in a number of cases,the federal government did not need the information at the fine level of resolution that the locals needed.Nonfederal stakeholders refused to maintain data at 1:100,000-scale because that is what the federal agencies needed for consistency,when they needed data at 1:12,000 for local needs.It became readily apparent that this was beyond a solely federal task --a National Spatial Data Infrastructure,including all potential players,was the only way to achieve this vision.