Fortunately, the inch is defined as 0.0254 meter exactly. So we have consistency for the really important units.
Then which "foot" is exactly 12.000000 inches?
Ending the Era of the U.S. Survey Foot
51–60 of 163 posts
Re: Ending the Era of the U.S. Survey Foot
#52Imagine it being 2020 and not using the metric system.
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Re: Ending the Era of the U.S. Survey Foot
#53The article left me confused about what it means to have a legally binding redefinition of a term. Does this mean that all existing, legally binding contracts are to be reinterpreted using the new definition of "foot"? Does it mean that any new legal document (contract, legislation, etc.) that uses the term "foot" without further clarification shall be assumed to mean this new definition of "foot"?
As a general point, I don't think contracts can have their terms adjusted after the fact without both parties agreeing to it.
Re: Ending the Era of the U.S. Survey Foot
#54Earlier quoted context omitted.
The difference is .0002%. your examples would barely add up to an inch over a mile.
Sometimes the benchmark for northing/easting/elev is many miles away from the actual site. This is especially true with gps surveys. It only takes a few inches to wind up with a substantial drainage problem.
Wouldn't the elevation difference between benchmark and site be the important bit here? If so, then the difference would rarely be more than a mile, and the resulting error would be at most an 1/8"
Re: Ending the Era of the U.S. Survey Foot
#55> In 1959, the relationship of the foot to the meter was officially refined as 1 foot = 0.304 8 meter exactly.
We can thank one man for this: Carl Edvard Johansson from Sweden. When making gauge blocks, he decided to round off the inch to exactly 25.4mm, and people around the world used his blocks to manufacture everything. The 1959 change just reflected what industry was already doing.
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Re: Ending the Era of the U.S. Survey Foot
#56I knew about the survey foot because both the l00' tape measures I have are in survey feet. Messed me up on a home construction project about 13 years back. It was then I learned there are 2 differing feet definitions.
Are you sure it was the differing length of each version (about 610 nanometers), or was it because your tapes were marked in tenths of a foot instead of inches?
Re: Ending the Era of the U.S. Survey Foot
#57Fortunately, the inch is defined as 0.0254 meter exactly. So we have consistency for the really important units.
Then which "foot" is exactly 12.000000 inches?
The International one (i.e. Non Survey Foot)
> In 1959, the relationship of the foot to the meter was officially refined as 1 foot = 0.3048 meter exactly.
So 0.0254 * 12.000000 == 0.3048
Re: Ending the Era of the U.S. Survey Foot
#58I knew about the survey foot because both the l00' tape measures I have are in survey feet. Messed me up on a home construction project about 13 years back. It was then I learned there are 2 differing feet definitions.
Over the length of a 100’ tape, the difference is about 61 um, ie 0.061 mm. How could that difference have any effect?
Re: Ending the Era of the U.S. Survey Foot
#59Re: Ending the Era of the U.S. Survey Foot
#60Fortunately, the inch is defined as 0.0254 meter exactly. So we have consistency for the really important units.
Then which "foot" is exactly 12.000000 inches?
My calculation shows 12 * 0.0254 = 0.30479999999999996 meters. That may be off a little due to IEEE floating-point inaccuracy.