The "Air Miles" you seem to be referring to are those used by airlines for calculating frequent flyer mileage. This is generally the point to point distance between any two airports using a great circle track. I have software that gives this in Nautical miles, multiply by 1,15 and you get Statute miles. This becomes the mileage or kilometers you get on your frequent flier statement. I've checked this out by using the distance from both DCA (Washington National) to ORD (Chicago O'Hare)531 NM or 610 SM, and IAD (Washington Dulles) to ORD, 510 NM or 586 SM. I don't think they take into account any departure or arrival tracks or other routings. Air miles is really direct distance in statute miles between two airports, As opposed to road miles which can be much greater.
Michael Payne > [Original Message] > From: Pat Naughtin <[EMAIL PROTECTED]> > To: U.S. Metric Association <[EMAIL PROTECTED]> > Date: 15/10/03 18:22:51 > Subject: [USMA:27182] Air miles > > Dear Phil, > > I think that you are right =AD 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 =AD > 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 =AD > 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 betwee= > n > the world's major airports, that allows for the extra distances that must b= > e > 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 t= > o > 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 =AD for example, if you do a search on Googl= > e > 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 acceptabl= > e > > 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 acceptabl= > e > > for use with SI. > > Right from the BIPM: > >=20 > >> From Table 8. Other non-SI units currently accepted for use with the > > International System > > Name Symbol Value in SI units > >=20 > > nautical mile (a) 1 nautical mile =3D 1852 m > >=20 > > (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. > >=20 > >=20 > > Phil > >=20 > > -----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 > >=20 > >=20 > > ? 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 litt= > le > > about metrology issues. > >=20 > > It's the same kind of thing with this hideous 'air miles' as if adding th= > e > > 'air' to the word it would make any difference!!! (I know, I know... thi= > s > > is 1.850 2 km we're talking about here, but still...) > >=20 > > I dream of the day we would simply create a 'km' program for air travel..= > . > > Sigh... > >=20 > > Warm regards, my dear friend, Han. > >=20 > > Marcus > >=20 > > On Mon, 13 Oct 2003 19:07:25 > > Han Maenen wrote: > >> Dear Pat, > >>=20 > >> 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. > >>=20 > >> Han > >>=20 > >>=20 > >> ----- 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 > >>=20 > >>=20 > >> Dear Han, > >>=20 > >> Your expression 'lineal km' strikes me as being redundant (if not > >> tautological). > >>=20 > >> Since length, in SI, has only one unit - the metre - and the metre is th= > e > >> 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. > >>=20 > >> If you use the expression km^1 you are saying that the one dimensional u= > nit > >> of the quantity length - the km - is one dimensional. > >> As I said, either the first of these is redundant (or tautological) or t= > he > >> second of these is tautological (or redundant). Sorry for the confused w= > ay > >> that I've written this, but I never fully understood the difference betw= > een > >> tautological and redundant - if any. > >>=20 > >> By the way, I once posted a notice on my office door that said: > >>=20 > >> Department of > >> Tautological Redundancies > >> Department > >>=20 > >> Apply Without > >>=20 > >> Cheers, > >>=20 > >> 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 > >> -- > >>=20 > >> on 12/10/03 7:06 AM, Han Maenen at [EMAIL PROTECTED] wrote: > >>=20 > >>> Pat, > >>>=20 > >>> 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. > >>>=20 > >>> 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 an= > d > >>> 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 increas= > e > >> our > >>> storage to 25 linear km. > >>>=20 > >>> As I cannot use superscript in Outlook Express I have written the symbo= > l > >> of > >>> linear km as km^1. > >>>=20 > >>> 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. > >>>=20 > >>> Best greetings, > >>>=20 > >>> Han > >>>=20 > >>>=20 > >>> ----- 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 > >>>=20 > >>>=20 > >>> on 2003-10-09 03.15, Han Maenen at [EMAIL PROTECTED] wrote: > >>>=20 > >>> <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. > >>>=20 > >>> Dear Han, > >>>=20 > >>> It makes you realise the genius of Simon Stevin, when you consider his > >>> physical and intellectual surroundings. > >>>=20 > >>> 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 numera= > l > >>> denominator. > >>>=20 > >>> I didn't check his calculations for accuracy - I took Simon's word for > > it! > >>>=20 > >>> 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. > >>>=20 > >>> Cheers, > >>>=20 > >>> Pat Naughtin LCAMS > >>> Geelong, Australia > >>>=20 > >>> 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] > >>> -- > >>>=20 > >>=20 > >>=20 > >>=20 > >=20 > >=20 > > ____________________________________________________________ > > Get 25MB of email storage with Lycos Mail Plus! > > Sign up today -- http://www.mail.lycos.com/brandPage.shtml?pageId=3Dplus > >=20 --- Michael Payne --- [EMAIL PROTECTED] --- EarthLink: The #1 provider of the Real Internet.
