Dear John,
Thanks for that; I like your argument. I will use it in future when it
comes to question time at my metrication presentations.
When someone uses an inch in a question such as, 'Isn't a horse
measured in inches?, I reply, Which inches do you mean – do you mean
the Imperial inch 0f 1824, the pendulum inch of 1834 when the UK
Parliament burned down, the other Imperial inch of 1845, or the
international (English speaking) inch of 1959? And now I can add, 'Or
do you mean an inch associated with one or other of the various
statute miles?'
Cheers and thanks,
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
for more metrication information, contact Pat at [email protected]
or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
On 2010/04/22, at 08:45 , John M. Steele wrote:
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.
