[Federal Register Volume 62, Number 15 (Thursday, January 23, 1997)]
[Notices]
[Page 3518]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1593]


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DEPARTMENT OF THE INTERIOR
Geological Survey


Federal Geographic Data Committee (FGDC); Public Review of 
Geospatial Positioning Accuracy Standards

ACTION: Notice; request for comments.

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SUMMARY: The FGDC is sponsoring a public review of the draft Geospatial 
Positioning Accuracy Standards to be considered for adoption as FGDC 
standards. If adopted, the standards must be followed by all Federal 
agencies for geospatial data collected directly or indirectly, through 
grants, partnerships, or contracts.
    In its assigned leadership role for developing the National Spatial 
Data Infrastructure (NSDI), the FGDC recognizes that the standards must 
also meet the needs and recognize the views of State and local 
governments, academia, industry, and the public. The purpose of this 
notice is to solicit such views. The FGDC invites the community to 
review, test, and evaluate the proposed standards. Comments are 
encouraged about the content, completeness, and usability of the 
proposed standard.
    The FGDC anticipates that the proposed standards will be adopted as 
Federal Geographic Data Committee standards after updating or revision. 
The standards may be forwarded to voluntary standards bodies for 
adoption if interest warrants such actions.

DATES: Comments must be received on or before May 15, 1997.

CONTACT and ADDRESSES: Requests for written copies of or review 
comments for the ``Geospatial Positioning Accuracy Standards'' should 
be addressed to Geospatial Positioning Accuracy Standards Review, FGDC 
Secretariat (attn: Jennifer Fox), U.S. Geological Survey, 590 National 
Center, 12201 Sunrise Valley Drive, Reston, Virginia, 20192; telephone 
703-648-5514; facsimile 703-648-5755; or Internet ``[email protected].'' The 
standard may be downloaded from this Internet address: ftp://
www.fgdc.gov/pub/standards/Accuracy/.

SUPPLEMENTARY INFORMATION: The Geospatial Positioning Accuracy 
Standards provide a common methodology for reporting the horizontal and 
vertical accuracy of clearly defined features where the location is 
represented by a single point coordinate: examples are survey 
monuments; prominent landmarks, such as church spires, standpipes, 
radio towers, tall chimneys, and mountain peaks; and targeted 
photogrammetric control points. It facilitates the interoperability of 
spatial data by providing a consistent means for users to directly 
compare positional accuracies obtained by different methods for the 
same point. It addresses positional accuracy reporting and testing 
requirements for various spatial data applications. The document 
consists of the following parts:
    Part 1, Reporting Methodology: The general accuracy reporting 
standard for the horizontal component is the radius of a circle of 
uncertainty, such that the true (theoretical) location of the point 
falls within the circle 95-percent of the time. The general accuracy 
reporting standard for the vertical component is a linear uncertainty 
value, such that the true (theoretical) location of the point falls 
within +/- of that linear uncertainty value 95-percent of the time. 
This reporting methodology is adopted in the subsequent parts of the 
draft standard.
    Part 2, Standards for Geodetic Networks. Part 2 addresses accuracy 
reporting for geodetic surveys. Geodetic control surveys are usually 
performed to establish a basic control network from which supplemental 
surveying and mapping work are performed. Geodetic network surveys are 
distinguished by use of redundant, interconnected, permanently 
monumented control points that comprise the framework for the National 
Spatial Reference System (NSRS) or are often incorporated into the 
NSRS. This standard is intended to replace accuracy standards 
previously issued by the Federal Geodetic Data Subcommittee.
    Part 3, National Standard for Spatial Data Accuracy. The National 
Standard for Spatial Data Accuracy (NSSDA) provides a common 
methodology for testing and reporting accuracy of maps and geospatial 
data derived from sources such as aerial photographs, satellite 
imagery, and maps. The NSSDA is intended to replace the United States 
National Map Accuracy Standards (U.S. Bureau of the Budget, 1947).
    The NSRS may be used to reference mapping project control surveys 
to a common georeference system. The accuracy of geospatial data 
derived from project control surveys is expressed using the NSSDA. The 
NSSDA also may be related to the NSRS by using NSRS points as check 
points to test accuracy of geospatial data derived from aerial 
photographs, satellite imagery, maps, and other secondary sources.

    Dated: January 14, 1997.
Richard E. Witmer,
Acting Chief, National Mapping Division.
[FR Doc. 97-1593 Filed 1-22-97; 8:45 am]
BILLING CODE 4310-31-M