[Federal Register Volume 84, Number 201 (Thursday, October 17, 2019)]
[Notices]
[Pages 55562-55565]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-22414]


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DEPARTMENT OF COMMERCE

National Institute of Standards and Technology


Deprecation of the United States (U.S.) Survey Foot

AGENCY: The National Institute of Standards and Technology and the 
National Geodetic Survey (NGS), National Ocean Service (NOS), National 
Oceanic and Atmospheric Administration (NOAA), Department of Commerce 
(DOC).

ACTION: Notice; request for comment.

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SUMMARY: The National Institute of Standards and Technology (NIST) and 
the National Geodetic Survey (NGS), National Ocean Service (NOS), 
National Oceanic and Atmospheric Administration (NOAA), are taking 
collaborative action to provide national uniformity in the measurement 
of length. This notice announces a decision to deprecate the use of the 
``U.S. survey foot'' on December 31, 2022. After that date, the ``U.S. 
survey foot'' will be superseded by the ``foot'' (formerly known as the 
``international foot''), which is already in use throughout the U.S. 
This notice describes the plan, resources, training, and other 
activities of NIST and NOAA that will assist those affected by this 
transition, and invites comments and other information from land 
surveyors, engineers, Federal, State and local government officials, 
businesses, and any other member of the public engaged in or affected 
by surveying and mapping operations.

DATES: Comments and other information must be received by December 2, 
2019.

ADDRESSES: NIST and NOAA are using the https://www.regulations.gov 
system for the submission and posting of public comments in this 
proceeding. All comments in response to this notice are therefore to be 
submitted electronically through https://www.regulations.gov, via the 
web form accessed by following the ``Submit a Formal Comment'' link 
near the top right of the Federal Register web page for this notice.

FOR FURTHER INFORMATION CONTACT: 
    U.S. survey foot deprecation resources: https://www.nist.gov/pml/us-surveyfoot.
    Information on standards development and maintenance: Elizabeth 
Gentry, 301-975-3690, [email protected].
    Technical and historical information on usage of the foot: Michael 
Dennis, 240-533-9611, [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    This action is designed to establish national uniformity in length 
measurements based on the foot. For more than sixty years, two nearly 
identical definitions of the foot have been in use in the U.S. for 
geodetic and land surveys. A Federal Register notice published on July 
1, 1959 (24 FR 5348) by the National Bureau of Standards (renamed the 
National Institute of Standards and Technology in 1988) and the U.S. 
Coast and Geodetic Survey (reorganized as the National Geodetic Survey 
under the National Oceanic and Atmospheric Administration in 1970) 
refined the definition of the yard in terms of the International System 
of Units (SI), commonly known as the metric system. The 1959 notice was 
issued after an international agreement among six nations resolved a 
long-standing difference in the relationship of the U.S. yard to the 
British yard. The notice reported that there was a slight difference (2 
parts per million) between the 1959 definition (i.e., one yard = 0.914 
4 meter, exactly) and an 1893 definition (i.e., 1 yard = 3600/3937 
meter, or approximately 0.914 401 83 meter).
    The 1959 Federal Register notice then adopted a revised value for 
the foot for use throughout the U.S., and identified it as the 
``international foot'' to show that it corresponded with the foot in 
use by the United Kingdom and other countries. The notice defined this 
international foot as 0.304 8 meter (e.g., equal to 0.999 999 8 of the 
value for the foot officially adopted in 1893). Additionally, to avoid 
disrupting the surveying practices at the time, the

[[Page 55563]]

notice established an interim approach that permitted the limited use 
of the historic 1893 value of the foot exclusively in the field of 
geodetic surveys. It was identified as the ``U.S. survey foot'' with 
the defined value of 0.304 800 61 meter (approximately). The 1959 
notice specifically stated that the ``U.S. survey foot'' should be used 
``until such a time as it becomes desirable and expedient to readjust 
the basic geodetic survey networks in the United States, after which 
the ratio of a yard, equal to 0.914 4 meter, shall apply.''
    As announced in a Federal Register notice published on March 24, 
1977 (42 FR 15943), NOAA officially adopted the meter as the unit for 
length in the National Spatial Reference System (NSRS). However, U.S. 
surveying and mapping practitioners continued to use the ``U.S. survey 
foot,'' including when they employed the NGS-defined State Plane 
Coordinates System of 1927 and 1983 (SPCS 27 and SPCS 83, 
respectively). Because the ``international foot'' is the basis for all 
other length measurements and calibrations in the U.S., it is no longer 
necessary to continue to maintain two unit values for the foot.

Consequences for Surveying, Mapping, and Engineering in the United 
States

    Although the use of the ``U.S. survey foot'' was intended to be an 
interim measure, its use continues to be prevalent in land surveying 
and mapping in much of the U.S. Of the 50 U.S. jurisdictions that have 
legislated SPCS 83 (48 States plus Puerto Rico and Guam), the ``U.S. 
survey foot'' has been specified for SPCS 83 in 40 States, either 
through statute (28 States) or Federal Register notices (12 States). 
Six States have adopted the ``international foot'' for SPCS 83, while 
two States (plus Puerto Rico and Guam) have not formally designated the 
type of foot to be used. It is important to note that State legislation 
and Federal Register notices regarding the ``U.S. survey foot'' are 
specifically associated with SPCS 83, and therefore are not applicable 
to the NSRS Modernization in 2022.
    It is also important to note that while the difference between the 
two definitions is 2 parts per million, this small discrepancy 
accumulates over large distances and can result in significant errors 
in surveying and civil engineering projects, regardless of the size of 
the project. For example, when a one-mile distance is surveyed, the 
difference is approximately 0.01 ft or 0.12 in. However, the impact 
becomes substantial when longer distance measurements or conversions 
are made, such as those involving rectangular plane coordinates of SPCS 
83. In these cases, the difference between the two definitions can also 
result in large direction and position location errors, in many cases 
reaching tens of feet for SPCS 83 coordinates.
    Because of this situation, there has been a long history of 
misunderstandings and confusion over which definition of the foot was 
used to carry out a specific land survey or civil engineering project. 
There have been many instances where software or electronic surveying 
devices default to one or the other foot definitions, but users 
incorrectly assume the actual unit of measure in use. This ongoing 
ambiguity has resulted in professional liability by the inadvertent 
violation of State law, the introduction of systematic errors in 
surveying and engineering projects, misreported position and location, 
land sale and project delays, boundary disputes, additional costs 
associated with correcting unit mistakes, and other unintended 
consequences. Because State jurisdictions with different legal 
definitions of the foot share borders, mapping projects in these 
geographic zones may experience elevated error risks as a surveyor 
transitions between a State that uses the ``U.S. survey foot'' and a 
State that uses the ``international foot.'' This risk is exacerbated 
when professional surveyors and engineers are licensed to practice in 
multiple States that use different versions of the foot, and for large 
projects when the team participants come from different States and even 
different countries. In addition to the cost due to errors, there is 
the cost of inefficiency, since it is necessary to keep track of the 
foot version, which increases with the size, duration, and complexity 
of projects.

Opportunity To Eliminate Confusion

    Since the publication of the 1959 Federal Register notice, 
experience has overwhelmingly revealed that national uniformity cannot 
be ensured in this critical industry field when users are routinely 
confronted with two definitions of the foot. The best opportunity for 
eliminating the redundancy in values for the foot will occur with the 
NOAA program to modernize the NSRS in 2022.
    The only practical solution is to deprecate the ``U.S. survey 
foot'' and to require that its use in surveying, mapping, and 
engineering be discontinued. Allowing the continued use of two 
definitions of the foot undercuts the value and benefit of national 
uniformity, and allows for additional opportunities for confusion and 
unnecessary costs to the users, the States, and professionals in the 
surveying, mapping, and engineering fields. No compelling justification 
to maintain two definitions for the foot exists.

Notice From the Director of the National Institute of Standards and 
Technology Regarding the Deprecation of the ``U.S. Survey Foot'' on 
December 31, 2022

    Under Article 1, Section 8 of the United States Constitution, 
Congress retains the power to ``fix the Standard of Weights and 
Measures.'' Throughout that section, the words ``uniform throughout the 
United States'' are used in conjunction with many of the other duties 
and responsibilities that are listed. The ``fixing'' or defining the 
standards of weights and measures is intrinsic to ensure uniform 
measurement across the U.S., as well as with the rest of the world. In 
1866, Congress acted to make the metric system of measurement (now 
known as the International System of Units (SI)) legal for use in the 
United States (15 U.S.C. 204). On May 20, 1875 the U.S. signed the 
Meter Convention (known as the ``International Treaty of the Meter''), 
which established the International Bureau of Weights and Measures, an 
intergovernmental organization under the General Conference on Weights 
and Measures that oversees the International Committee for Weights and 
Measures, which is the organization that maintains the SI to meet the 
measurement needs of the world. On April 5, 1893, the ``Mendenhall 
Order,'' issued by the U.S. Coast and Geodetic Survey with the approval 
of the U.S. Secretary of the Treasury, determined that the U.S. 
Customary units of the yard and pound would be defined in terms of the 
SI units of the meter and kilogram. The practice of defining the U.S. 
Customary units of measurement in terms of the SI continues today.
    In 1988, Congress declared that the metric system was the preferred 
system of measurement for trade and commerce in the United States (15 
U.S.C. 205b). The Director of the National Institute of Standards and 
Technology is authorized by statute ``to develop, maintain, and retain 
custody of the national standards of measurement, and provide the means 
and methods for making measurements consistent with those standards'' 
(15 U.S.C. 272(b)(2)), ``to assure the compatibility of United States 
national measurement standards with those of other nations'' (15 U.S.C. 
272(b)(9)), and to ``cooperate with the States in securing uniformity 
in weights and measures laws'' (15 U.S.C. 272(c)(4)). Under this

[[Page 55564]]

authority, the SI is interpreted or modified by the Director of NIST 
for use in the United States. The SI is used exclusively to define, 
establish, and maintain the U.S. national standards of measurement and 
in securing uniformity of their use in the laws of the States.
    ``Deprecation'' is a term widely used in the field of legal 
metrology and other measurement science fields of study. It describes a 
decision to discontinue the use of a specific measurement unit or 
method of sale. A unit of measurement (e.g., the foot or gallon) though 
legal, may be prohibited from being used in a specific commercial 
application if, for example, it has been identified as being redundant 
or a source of confusion, or if it could frustrate the ability of users 
to make quantity and value comparisons. For example, gasoline and other 
engine fuels are permitted to be sold from a retail service station by 
the gallon but may not be sold by the fluid pint or fluid ounce. As the 
situation with multiple definitions for the foot illustrates, 
measurement unit uniformity is only possible when a single measurement 
unit definition is used for a specific application (e.g., land 
surveying).
    The deprecation process begins with a notice to users that a unit 
of measure is to be deprecated and that use of the unit is to be 
avoided after a specific date. The notice also prescribes the new unit 
of measurement that will be accepted for use. The notice period allows 
users time to make the necessary changes to their measuring practices, 
processes, procedures, and devices. The notice period also provides an 
opportunity for education and training for all of those involved in the 
changeover and the identification of unforeseen issues so that 
appropriate preventive actions, exceptions, or additional requirements 
can be developed and implemented. After the notice period ends, the 
deprecated measurement unit is deemed obsolete, its use is to be 
avoided, and it is retained for historical purposes and legacy 
applications only.

Deprecation of the Survey Foot, Survey Mile, and Other Measures Derived 
From the Survey Foot

    On December 31, 2022, the 1893 ``U.S. survey foot,'' as defined in 
a 1959 Federal Register notice (24 FR 5348, June 30, 1959), will be 
deprecated as a U.S. national standard of measurement and its use is to 
be avoided. The 1893 definition of the ``U.S. survey foot'' will be 
retained for historic reference but will be deemed obsolete. This 
notice also applies to the ``U.S. survey mile'' (equal to approximately 
1609.347 meters), which is based on the ``U.S. survey foot,'' the use 
of which should also be avoided after December 31, 2022 and which will 
be retained for historical purposes but will be deemed obsolete. After 
December 31, 2022, any data derived from or published as a result of 
surveying, mapping, or any other activity within the U.S. that is 
expressed in terms of feet shall only be based on the ``foot'' equal to 
0.304 8 meter (exactly), formerly known as the ``international foot'' 
in the 1959 Federal Register notice.
    Likewise, other measures previously based only on the ``U.S. survey 
foot'' will be defined using the foot equal to 0.304 8 meter (exactly) 
after December 31, 2022. These measures are the ``chain,'' ``link,'' 
``rod'' (also ``pole'' or ``perch''), ``furlong,'' and ``fathom'' for 
length, and the ``acre'' for area. Decimal SI equivalents for these 
measures are given in Table 1 for both the ``U.S. survey foot'' 
(approximate) and the ``foot'' (exact). For these measures, the 
difference between the two types of feet is usually of no practical 
consequence. For example, the greatest precision typically used for the 
chain in modern land surveying practice is three decimal places (or 0.1 
link), and at that level of significance both versions of the foot give 
the same value. Similarly, the difference in area for 1 acre is only 
0.000 004 acre (0.17 ft\2\) for the two foot versions.

    Table 1--Approximate Decimal SI Equivalents for Measures Commonly Given in ``U.S. Survey Feet'' and Exact
Equivalents for the ``Foot'' That Will Be Adopted After December 31, 2022 in NIST SP 811, The NIST Guide for the
                                    use of the International System of Units
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                                                            ``U.S. survey
  Unit of measure based on feet      Type of quantity           foot''                 ``foot'' (exact)
                                                            (approximate)
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foot (ft)........................  length..............  0.304 800 6 . . . m  0.304 8 m
mile (mi)........................  length..............  1609.347 . . . m...  1609.344 m
chain (ch).......................  length..............  20.116 84 . . . m..  20.116 8 m
link (li)........................  length..............  0.201 168 4 . . . m  0.201 168 m
rod (rd), pole, perch............  length..............  5.029 21 . . . m...  5.029 2 m
furlong (fur)....................  length..............  201.168 4 . . . m..  201.168 m
fathom...........................  length..............  1.828 804 . . . m..  1.828 8 m
acre (ac)........................  area................  4046.872 609 9 . .   4046.856 422 4 m\2\
                                                          . m\2\.
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    In keeping with the terms of this notice, the ``U.S. survey foot'' 
will no longer be supported by NOAA in the modernized NSRS after 2022, 
including the State Plane Coordinate System of 2022 (SPCS2022), 
elevations, and all other components of the system. However, the ``U.S. 
survey foot'' will be permanently maintained in NOAA products and 
services for legacy applications, for example the computation of SPCS 
coordinates in States where it was specified for SPCS 83, and for all 
zones of SPCS 27.

Comments and Future Action

    The Director of NIST and the Director of the National Geodetic 
Survey (NGS) solicit comments and suggestions from land surveyors, 
engineers, Federal, State and local officials, equipment manufacturers, 
and the public at large who are engaged in or affected by surveying and 
mapping operations for ways that the two agencies can help facilitate 
an orderly transition to a single definition for the foot. Throughout 
the notice period, NGS and the NIST Office of Weights and Measures will 
work together to provide opportunities for education and training for 
all of those involved in the changeover. After the public comments are 
evaluated, any unforeseen issues identified, and appropriate solutions 
developed, a second Federal Register notice addressing those issues 
will be published and publicly announced in other media as appropriate 
before June 30, 2020.
    This action is being taken in conjunction with the NGS program to 
improve the National Spatial Reference System (NSRS), as described at 
https://geodesy.noaa.gov/datums/newdatums/

[[Page 55565]]

index.shtml. In 2022, NGS will replace the North American Datum of 1983 
(NAD 83) and the North American Vertical Datum of 1988 (NAVD 88) with 
new geometric reference frames and a geopotential datum. The new 
reference frames and datum will rely primarily on Global Navigation 
Satellite Systems (GNSS), such as the Global Positioning System (GPS), 
as well as on a gravimetric geoid model resulting from the NGS Gravity 
for the Redefinition of the American Vertical Datum (GRAV-D) Project. 
These new reference frames and datum will be easier to access and 
maintain than NAD 83 and NAVD 88, which rely on physical survey marks 
that deteriorate over time.
    On April 18, 2018, NGS issued a draft Federal Register notice (83 
FR 17149) for public comment on draft policy and procedures for the 
State Plane Coordinate System of 2022 (SPCS2022), which will be 
referenced to the 2022 reference frames. In those draft documents, it 
was specified that SPCS2022 parameters will be exclusively defined 
using metric (SI) values. However, in addition to metric values, the 
documents stated that output coordinates could also optionally be 
provided in either ``international'' or ``U.S. survey feet,'' and that 
by default the type of foot would be the same as currently used for 
SPCS 83. The official version of SPCS2022 Policy, effective April 23, 
2019 (https://geodesy.noaa.gov/INFO/Policy/files/SPCS2022_Policy_NGS_2019-1214-01.pdf), states that NGS has not yet 
determined whether or what type of foot will be supported for output 
coordinates (Section II.E.1). The policy will be updated after NIST and 
NOAA co-issue a Federal Register notice by June 30, 2020, announcing 
adoption of the ``foot'' equal to 0.304 8 meter (exactly) as the 
official definition for all applications in the U.S. after December 31, 
2022.

Kevin A. Kimball,
Chief of Staff.
[FR Doc. 2019-22414 Filed 10-16-19; 8:45 am]
 BILLING CODE 3510-13-P