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Introduction
The National Oceanic and Atmospheric Administration (NOAA) has a mandated responsibility to establish and maintain a geodetic reference system. NOAA's National Geodetic Reference System (NGRS) was originally established using classical surveying techniques and is used primarily by federal, state, and local governments, and utility companies to maintain uniformity in land surveys. With the advent of the Global Positioning System (GPS), and its availability for civilian use, it is now possible to obtain four-dimensional position data that are economical and horizontally is an order of magnitude more accurate than data obtained from the NGRS.
At the same time, the number and diversity of users of spatial data has increased to such an extent that there is a need for a national spatial data infrastructure to which all mapping, surveying, navigation/transportation, crustal motion studies, and geographic information systems can be referenced. With the widespread availability of low-cost GPS receivers, it is now possible to create a more accurate and useful geodetic reference system. The National Geodetic Survey (NGS), operating through the National Ocean Service (NOS) of NOAA, has responded by proposing a National Spatial Reference System (NSRS), which would have the following components:
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a network of points having four-dimensional positions that are monumented and maintained for reliability and ease of use,
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a set of GPS Continuously Operating Reference Stations (CORS) with data available at a high sampling rate, 24 hours a day,
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high accuracy orbital determinations of the GPS satellites,
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a highly accurate geoid.
The framework for the NSRS and the role of the NGS in implementing it are outlined in the 1994 NOAA documents, National Geodetic Survey: Its Mission, Vision, and Strategic Goals, and Draft Implementation Plan for the National Spatial Reference System. The NOS asked the National Research Council's (NRC) Committee on Geodesy (COG) to review the documents (hereafter referred to as the Strategic Goals and the Implementation Plan, respectively) in the context of the national need for a coordinated spatial data reference system. The COG responded by organizing a forum to obtain input from the current and potential user communities. To manage the forum, the COG established a steering committee
consisting of Elizabeth Cannon, Clifford Greve, Robert Packard, Richard Sailor, William Young (chair), and Anne Linn as the NRC Program Officer.
Forum participants were selected to represent the major spatial data user communities, including geodesy and geophysics research, highway, railroad, marine, and air transportation, geographic information systems, surveying, oil industry, and GPS applications. Participants included scientists from universities, federal agencies, and industry, consultants, state and local government surveyors, and representatives from NOAA and federal agencies that administer programs in geodesy or spatial data. NRC committees nominated the forum participants; federal sponsors were invited by the COG and by NOAA. Appendix C contains a list of the forum participants.
The forum was structured to provide an opportunity for the user communities to interact with the individuals responsible for the design and implementation of the NSRS. Introductory presentations focused on the NSRS and its place in NOAA's overall strategy (Appendix B). Participants in the forum were asked to consider the plans for the NSRS from two perspectives. In advance of the forum, eleven individuals, representing several user communities, prepared written critiques of aspects of the Strategic Goals. The Implementation Plan was not available in time to be reviewed before the forum. The individuals were asked to prepare 1-2 pages of bullets on the following questions:
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Is the NSRS compatible with systems currently used in your community?
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Does the NSRS meet the current and future needs of your community? Why/why not?
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What are the three key Strategic Goals for your community? Are there other goals that should be incorporated in the NSRS?
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Does your community need a link to NOAA for assistance in implementing the NSRS? If so, what form should that link take?
The authors presented their critiques at the forum, and the animated discussions that followed provided immediate feedback to the federal sponsors. The critiques are shown, as written, in Appendix A.
Next, forum participants were divided into multi-disciplinary working groups to discuss the following questions about the Strategic Goals and Implementation Plan:
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Does the NSRS incorporate current measurement technology and anticipate future technological developments?
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in data acquisition?
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in data management?
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in distribution of spatial data?
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What technological or research initiatives are needed to remedy any shortfalls?
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How can the Strategic Goals/Implementation Plan be modified to encourage more widespread use of the NSRS as the nation moves toward advanced navigation systems and the National Spatial Data Infrastructure? What initiatives are needed to bring this about?
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How can NOAA educate potential spatial data users of the advantages of the NSRS?
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Is the proposed density and distribution of points in the network adequate to meet the needs of your sphere of interest? How can federal-state-local government-private sector partnerships be forged to help increase the density of points in the network?
No attempt was made to review comprehensively the Strategic Goals or Implementation Plan. The four working group chairs presented summaries of their conclusions at a final plenary session of the forum. These summaries comprise the third chapter of this report. The conclusions and concerns that were common to several working groups and/or written critiques are summarized in the next chapter. Although the federal sponsors were encouraged to ask and answer questions in the plenary sessions and working groups, the conclusions and recommendations of this report are based largely on input from the NRC-invited participants, the COG, and the experience of members of the steering committee.
