I agree that as far as passengers on commercial airlines are concerned, it makes sense to quote all speeds and distances in km/h and km. That said, metric advocates need to understand why nautical miles are so important that the BIPM made the decision to accept them for use with the SI.
Most of the world measures angles in degrees, and geographic location in degrees, minutes, and seconds of latitude and longitude. Since one nautical mile is an arc minute of latitude, and 1 degree is 60 nautical miles, one can immediately grasp distances on a map directly from the coordinate grid. This is a whole lot quicker and easier than trying to use a scale in km. Furthermore, to calculate distances based on coordinates, you would probably find the distance in NM before multiplying by 1.852 to get it in km. It's obvious from the definition of the meter that the French had intended to replace the NM with the km by using decimal angles for maps and navigation. In conclusion, the "problem" is not nautical miles: it's the crazy way we measure angles. I wish the world had embraced decimal angles and the 1/100000 day second. Then kWh and km/h would be directly related to the SI units J and m/s by simple shifts of the decimal, and the geographic coordinates and grids on maps would already be tied to kilometers. John On Wednesday 15 October 2003 14:35, Phil Chernack 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
