diff --git a/CHANGES b/CHANGES index 1b2981430..fd5ff2c99 100644 --- a/CHANGES +++ b/CHANGES @@ -4,7 +4,7 @@ Pint Changelog 0.24 (unreleased) ----------------- -- Nothing changed yet. +- Updated definition of US survey units to reflect the 2022 revision by NIST/NGS 0.23 (2023-12-08) diff --git a/pint/default_en.txt b/pint/default_en.txt index 5fc7f8265..cd052fba1 100644 --- a/pint/default_en.txt +++ b/pint/default_en.txt @@ -538,23 +538,31 @@ neper = 1 ; logbase: 2.71828182845904523536028747135266249775724709369995; logfa cubic_yard = yd ** 3 = cu_yd @end +# Note: historically, many of the units in this group were derived from each other (e.g. 1 chain = 10 fathoms = 4 rods = 100 links) +# but we've followed the NIST's lead here and defined all of the units directly based on "common" units (feet and miles) +# Source: Warfield, L. , Konijnenburg, J. , Lippa, K. , Lee, G. , Minnich, L. and Williams, J. (2023), Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices as adopted by the 108th National Conference on Weights and Measures, Handbook (NIST HB), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.HB.44-2024 (Accessed January 12, 2024) @group USCSLengthSurvey - link = 1e-2 * chain = li = survey_link - survey_foot = 1200 / 3937 * meter = sft - fathom = 6 * survey_foot - rod = 16.5 * survey_foot = rd = pole = perch - chain = 4 * rod - furlong = 40 * rod = fur - cables_length = 120 * fathom - survey_mile = 5280 * survey_foot = smi = us_statute_mile - league = 3 * survey_mile - - square_rod = rod ** 2 = sq_rod = sq_pole = sq_perch - acre = 10 * chain ** 2 - square_survey_mile = survey_mile ** 2 = _ = section + cables_length = 720 * foot + chain = 66 * foot = ch + fathom = 6 * foot + furlong = 660 * foot = fur + league = 3 * mile + link = 0.66 * foot = li = survey_link + rod = 16.5 * foot = rd = pole = perch + + square_rod = rod ** 2 = sq_rd = sq_rod = sq_pole = sq_perch + acre = 43560 * square_foot square_league = league ** 2 + acre_foot = acre * foot = _ = acre_feet +@end - acre_foot = acre * survey_foot = _ = acre_feet +# The adoption of the international foot in 1959 temporarily permitted the continued use of the 1893 definition of the foot for survey purposes. +# That established the Survey Foot. After 2022, that exception was no longer permitted and all feet are feet (survey or otherwise). +# Source: Barton, J. , Blackwell, B. , Butcher, T. , Harshman, R., Lee, G. , Olson, D. (2019), Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices as adopted by the 108th National Conference on Weights and Measures 2019, Handbook (NIST HB), National Institute of Standards and Technology, Gaithersburg, MD, [online], h: https://doi.org/10.6028/NIST.HB.44-2020 (Accessed January 12, 2024) +@group USCSLengthSurveyMendenhall + survey_foot = 1200 / 3937 * meter = sft + survey_mile = 5280 * survey_foot = smi = us_statute_mile + square_survey_mile = survey_mile ** 2 @end @group USCSDryVolume