Pat, I see your point but I was going under the interpretation that regardless of how the distance is measured from point a to point b, the length of the unit of measurement used is 1850 m, defined as the nautical mile and air speeds are in knots. This is from a strictly navigational point of view.
If reference information is being given to laypeople on how far their flight is, I suppose "air mile" could be a staute mile or more appropriately should be expressed in km. I would hazard to guess most people don't know how to quantify a nautical mile (just like the excuse they can't quantify km in the US). Using your logic, the distance from my house in Caldwell, NJ to my friend's house in Brooklyn, NY is 25.5 statute miles or 41 km or 22.2 nautical miles traveling on I-280, to the Holland tunnel, through lower Manhattan, over the Williamsburg bridge into Brooklyn. It is certainly a much smaller distance "as the crow flies". BTW, the statement from table 8 clearly says "The nautical mile is a special unit employed for marine and *aerial* navigation to express distance." Phil -----Original Message----- From: Pat Naughtin [mailto:[EMAIL PROTECTED] Sent: Wednesday, October 15, 2003 6:23 PM To: Phil Chernack; U.S. Metric Association Subject: Air miles Dear Phil, I think that you are right � in part. I think that the word 'air' as it is used in 'air miles' does prove to usefully distinguish air miles from nautical miles. Let me give you an example. If a plane goes from new York to Seattle, then you could find the distance between the two cities with a ruler and a map that shows nautical miles. However, it is often the case that the plane can't go that (direct) way � let's suppose that it has to fly around the airspace of one or more intervening cities. In this case the plane would travel more nautical miles to allow for the diversion. This extra distance is allowed for by measuring the actual path that the plane takes, and by calling these 'air miles'. The distance travelled between the two cities is then specified as air miles � there are always more air miles between two cities than there are nautical miles. In addition, allowance has also to be made for other increases, such as airport effects that require planes to always take off in a particular direction to allow for weather or community (say curfew over a particular suburb) effects. I believe that there is an international table of air mile distances between the world's major airports, that allows for the extra distances that must be flown to allow for local effects, but I don't know where to find it. Jim Frysinger may have a source of these. The net result of these influences means that air miles invariably appear to be shorter than nautical miles, although they apparently share a common definition (1852 metres). Needless to say that this common definition leads to all sorts of misunderstanding � for example, if you do a search on Google for "nautical miles" "air miles" and you will see how many dictionaries think that nautical miles and air miles are exactly synonymous. On another issue, you said: > Air miles are the same as nautical miles, a non-SI unit that is acceptable > for use with SI. > Right from the BIPM: When I examined the BIPM we site at: http://www1.bipm.org/en/si/si_brochure/chapter4/4-1.html I could not find ant reference to the expression 'air miles'. Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is the editor of the free online newsletter, 'Metrication matters'. You can subscribe by sending an email containing the words subscribe Metrication matters to [EMAIL PROTECTED] -- on 16/10/03 7:35 AM, Phil Chernack at [EMAIL PROTECTED] wrote: > Air miles are the same as nautical miles, a non-SI unit that is acceptable > for use with SI. > Right from the BIPM: > >> From Table 8. Other non-SI units currently accepted for use with the > International System > Name Symbol Value in SI units > > nautical mile (a) 1 nautical mile = 1852 m > > (a) The nautical mile is a special unit employed for marine and aerial > navigation to express distance. The conventional value given above was > adopted by the First International Extraordinary Hydrographic Conference, > Monaco, 1929, under the name "International nautical mile". As yet there is > no internationally agreed symbol. This unit was originally chosen because > one nautical mile on the surface of the Earth subtends approximately one > minute of angle at the centre. > > > Phil > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Behalf Of Ma Be > Sent: Wednesday, October 15, 2003 12:36 PM > To: U.S. Metric Association > Subject: [USMA:27177] Re: Lineal kilometres > > > ? Even if it is true, Han, I must agree with my colleague here, km^1 is a > redundancy we can do without! Typical, evidently, of folks who know little > about metrology issues. > > It's the same kind of thing with this hideous 'air miles' as if adding the > 'air' to the word it would make any difference!!! (I know, I know... this > is 1.850 2 km we're talking about here, but still...) > > I dream of the day we would simply create a 'km' program for air travel... > Sigh... > > Warm regards, my dear friend, Han. > > Marcus > > On Mon, 13 Oct 2003 19:07:25 > Han Maenen wrote: >> Dear Pat, >> >> It is not me who adds ^1 to m or km, it is a standard in the world of >> archives and public records. Archivists feel they have a need for linear m >> and km. >> >> Han >> >> >> ----- Original Message ----- >> From: "Pat Naughtin" <[EMAIL PROTECTED]> >> To: "U.S. Metric Association" <[EMAIL PROTECTED]> >> Sent: Monday, 2003-10-13 1:51 >> Subject: [USMA:27161] Lineal kilometres >> >> >> Dear Han, >> >> Your expression 'lineal km' strikes me as being redundant (if not >> tautological). >> >> Since length, in SI, has only one unit - the metre - and the metre is the >> only dimension for length, then you don't need to note that km measures >> length by adding ^1 to km to form the symbol km^1. >> >> If you use the expression km^1 you are saying that the one dimensional unit >> of the quantity length - the km - is one dimensional. >> As I said, either the first of these is redundant (or tautological) or the >> second of these is tautological (or redundant). Sorry for the confused way >> that I've written this, but I never fully understood the difference between >> tautological and redundant - if any. >> >> By the way, I once posted a notice on my office door that said: >> >> Department of >> Tautological Redundancies >> Department >> >> Apply Without >> >> Cheers, >> >> Pat Naughtin >> LCAMS - Lifetime Certified Advanced Metrication Specialist >> - United States Metric Association >> ASM - Accredited Speaking Member >> - National Speakers Association of Australia >> Member, International Federation for Professional Speakers >> -- >> >> on 12/10/03 7:06 AM, Han Maenen at [EMAIL PROTECTED] wrote: >> >>> Pat, >>> >>> Yes, that was a nice example you gave and that kind of thing gave rise to >>> people who wanted change, like Simon Stevin and John Napier, who stood up >> a >>> few hundred years before decimal money and the metric system made their >>> debut. >>> >>> I got a remark from another list member about the 16 km^1. Although the >>> length of our storaged archives looks like hidden ifp trash, it is not. > Of >>> course, the BWMA would love it if the archives in continental Europe and >>> other metric countries used yards and miles as standard units. Too bad > for >>> them, no way. These 16 km^1 are purely co-incidental. Soon we will take >> over >>> the archives of Dutch Roman Catholicism, 9 linear km, that will increase >> our >>> storage to 25 linear km. >>> >>> As I cannot use superscript in Outlook Express I have written the symbol >> of >>> linear km as km^1. >>> >>> The cities of Arnhem and Nijmegen are planning to build a very large >> storage >>> room for public records and archives on a location between both cities. >>> >>> Best greetings, >>> >>> Han >>> >>> >>> ----- Original Message ----- >>> From: "Pat Naughtin" <[EMAIL PROTECTED]> >>> To: "U.S. Metric Association" <[EMAIL PROTECTED]> >>> Sent: Thursday, 2003-10-09 10:27 >>> Subject: [USMA:27143] Re: Curiosity from the archives >>> >>> >>> on 2003-10-09 03.15, Han Maenen at [EMAIL PROTECTED] wrote: >>> >>> <snip> >>>> Many financial calculations were made in Roman numerals and the money > was >>> not decimal as well. Present day archivists and researchers get in > trouble >>> with this stuff and have to master Roman numerals and non-decimal >>>> calculations. >>> >>> Dear Han, >>> >>> It makes you realise the genius of Simon Stevin, when you consider his >>> physical and intellectual surroundings. >>> >>> I can remember one of his papers bemoaning the severity of calculating >>> something like, 'What is the result of investing 324 pounds, 12 > shillings, >>> and 4 pence ha'penny for 17 years 8 months and a week at 3 7/8 per > cent?', >>> when all calculations were done in Roman numerals. As I remember it the >>> answer had a whole number with a 13 numeral numerator above a 17 numeral >>> denominator. >>> >>> I didn't check his calculations for accuracy - I took Simon's word for > it! >>> >>> However, I did think at the time that many hundreds of intellectually >> gifted >>> people must have been employed on these terribly pointless tasks. It's no >>> wonder that Simon Stevin was so delighted when he developed decimal >> numbers >>> and decimal calculations in 1585. >>> >>> Cheers, >>> >>> Pat Naughtin LCAMS >>> Geelong, Australia >>> >>> Pat Naughtin is the editor of the free online newsletter, 'Metrication >>> matters'. You can subscribe by sending an email containing the words >>> subscribe Metrication matters to [EMAIL PROTECTED] >>> -- >>> >> >> >> > > > ____________________________________________________________ > Get 25MB of email storage with Lycos Mail Plus! > Sign up today -- http://www.mail.lycos.com/brandPage.shtml?pageId=plus >
