On Thursday 08 October 2009 02:19:14 Pat Naughtin wrote: > Which yard do you mean? Are you talking about the 1859 metric-defined > international yard, the 1893 metric-defined yard, (the statute yard or > the survey yard of the USA), the interim yard between 1834 and 1855 > based on the length of a pendulum with no real fixed length, the 1855 > UK yard based on an artefact, the 1824 UK Imperial yard (1832 in the > USA) that got burned with the UK Houses of Parliament in 1834 or one > of the many earlier yards that appeared from time to time all with > slightly varying lengths (possibilities here are three Elizabeth I > feet, the Edward I ulna, or three Roman feet, etc.)?
For at least 99% of the problems that anyone in the US today is going to encounter, the answer is the yard defined as 0.9144 m exactly, and if not otherwise specified that is the one I would use. The 2 ppm longer survey yard is unlikely to come up, as surveyors use feet, chains, and links, but rarely yards. If I were in Texas it might be the somewhat shorter Spanish yard, or vara. And if there's a SWIM buffer on the subdivision, it would be a side yard. ;) Pierre
