Notice: Final Determination on Retiring the U.S. Survey Foot

NOAA's National Ocean Service sent this bulletin at 10/05/2020 02:00 PM EDT

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Final Determination on Retiring the U.S. Survey Foot

 

Platinum-iridium meter bars used as the standard of length in the U.S. from 1893 to 1960 (credit: NIST)

The National Institute of Standards and Technology (NIST) and NOAA’s National Geodetic Survey (NGS) have co-issued a Federal Register Notice (FRN) to retire the U.S. Survey Foot. This FRN announces the final decision to deprecate the U.S. survey foot on December 31, 2022.

 

After that date, the U.S. survey foot should not be used and will be superseded by the international foot definition (1 foot = 0.3048 meter exactly) in all applications. The international foot is currently used throughout the United States for most purposes and is typically referred to as simply the “foot.” Either the term “foot” or “international foot” may be used, as required for clarity in technical applications.

Summary of FRN Content

  • The deprecation date of December 31, 2022 is independent of any delays in implementing the modernized National Spatial Reference System (NSRS). For additional information, see the New Datum FAQs.

  • Only the international foot definition will be supported in the modernized NSRS. However, NGS will continue to support the U.S. survey foot for the State Plane Coordinate Systems of 1983 and 1927.

  • The FRN includes detailed descriptions of public comments and other input received and provides counterpoints to feedback expressing opposition to the change.

  • Exact international foot metric conversions are tabulated for units of measure previously defined only by the U.S. survey foot (such as the chain and acre).

  • Recommendations and resources are provided to facilitate an orderly transition for uniform nationwide adoption of the international foot definition.

 

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