Furlongs

Posted Jul 14, 2022 9:57 UTC (Thu) by nowster (subscriber, #67)
In reply to: Furlongs by nickodell
Parent article: Native Python support for units?

USA uses the survey mile. The rest of the world uses the statute mile (1760 yards). There's a 2ppm difference between them, as you note. The US standard yard changed in 1959 to match the International Yard, except for survey purposes. In the US references to a furlong (220 yards) are assumed to be based on the Survey Yard, not the International Yard.

And then we come on to volume measures...

Furlongs

Posted Jul 15, 2022 18:46 UTC (Fri) by NYKevin (subscriber, #129325) [Link]

The US only sometimes uses the survey units, most commonly in the context of surveying. As a result, you will sometimes see survey units used to define the borders of real estate parcels and such, but they are not the standard units that most Americans actually use on a day-to-day basis. For example, if you buy a foot-long ruler, it should be an international foot (i.e. 304.8 mm), not a survey foot. NIST and other federal agencies plan to phase out the survey units beginning in 2023, but they do plan to retain some legacy data in that format for backwards compatibility reasons.

Source: https://www.nist.gov/pml/us-surveyfoot