I would challenge that the "statute mile" is not the Survey Mile but is "undefined" in the United States, as a result of having two definitions. For all map and land measurement work based on old NAD27 datum, it was clearly the survey mile.
The original intent was that all geodetic work for the new NAD83 datum (essentially equivalent to WGS84, the world GPS datum) would be released in meters only, and it was initially. The States balked, and they were given a choice of having supplemental data in International or Survey feet, but the Legislature had to pass a law defining their choice. As the issue is apparently a bit of embarassment, I can't find a good summary anywhere, you basically have to search for the definition of each State's State Plane Coordinate System. However some have chosen Survey, some International, and some use the meter for SPCS (God knows what they use for miles on their road signs). I happen to live in an International Mile State. In reality the difference is minute and rarely matters, but it takes Customary forces aback when you argue the words "statute mile" mean nothing because they mean two things. When you force them to research it, they see it is true. The difference is only 2 ppm and that is less than the accuracy in routine surveying. However, most States have multiple zones to their SPCS and use large false origin values to ensure coordinates in different zones don't overlap and essentially encode the zone numbers. These false origins values are usually whole multiples of 1 million feet in northing and/or easting, so 2 feet per million matters. ________________________________ From: Pat Naughtin <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Wed, April 21, 2010 6:04:26 PM Subject: [USMA:47225] Statute miles – both of them Dear All, Statute miles – both of them The term "statute mile" originated with Queen Elizabeth I who changed the definition of the mile from the Roman mile of 5000 feet to the statute mile (UK) of 5280 feet. The international mile and the statute mile (USA) differ by about 3 millimetres although both are defined as being equal to 5280 feet. The international mile is based on the international foot (0.3048 metre exactly) whereas the statute mile (USA) is based on the survey foot (1200/3937 metre = 0.3048006 approximately). Cheers, Pat Naughtin Author of the ebook, Metrication Leaders Guide, that you can obtain from http://metricationmatters.com/MetricationLeadersGuideInfo.html PO Box 305 Belmont 3216, Geelong, Australia Phone: 61 3 5241 2008 Metric system consultant, writer, and speaker, Pat Naughtin, has helped thousands of people and hundreds of companies upgrade to the modern metric system smoothly, quickly, and so economically that they now save thousands each year when buying, processing, or selling for their businesses. Pat provides services and resources for many different trades, crafts, and professions for commercial, industrial and government metrication leaders in Asia, Europe, and in the USA. Pat's clients include the Australian Government, Google, NASA, NIST, and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com/ to subscribe.
