From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: distance from Easter Island to Chile Date: Sun, 20 Apr 2014 10:48:43 +0300 Message-ID: <83mwfgfnl0.fsf@gnu.org> References: <87mwfguasr.fsf@nl106-137-194.student.uu.se> NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1397980172 11362 80.91.229.3 (20 Apr 2014 07:49:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 20 Apr 2014 07:49:32 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Apr 20 09:49:23 2014 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WbmV9-0006OW-A2 for geh-help-gnu-emacs@m.gmane.org; Sun, 20 Apr 2014 09:49:23 +0200 Original-Received: from localhost ([::1]:44700 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WbmV8-00015n-VP for geh-help-gnu-emacs@m.gmane.org; Sun, 20 Apr 2014 03:49:22 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:44783) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WbmUs-00015g-GJ for help-gnu-emacs@gnu.org; Sun, 20 Apr 2014 03:49:12 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WbmUj-0000xW-Mb for help-gnu-emacs@gnu.org; Sun, 20 Apr 2014 03:49:06 -0400 Original-Received: from mtaout22.012.net.il ([80.179.55.172]:61195) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WbmUj-0000xM-E9 for help-gnu-emacs@gnu.org; Sun, 20 Apr 2014 03:48:57 -0400 Original-Received: from conversion-daemon.a-mtaout22.012.net.il by a-mtaout22.012.net.il (HyperSendmail v2007.08) id <0N4B00M00K7R1F00@a-mtaout22.012.net.il> for help-gnu-emacs@gnu.org; Sun, 20 Apr 2014 10:48:56 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout22.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0N4B00LRNKDJWL30@a-mtaout22.012.net.il> for help-gnu-emacs@gnu.org; Sun, 20 Apr 2014 10:48:56 +0300 (IDT) In-reply-to: X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 X-Received-From: 80.179.55.172 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:97250 Archived-At: > From: Barry Margolin > Date: Sun, 20 Apr 2014 03:01:36 -0400 > > In article , > Eli Zaretskii wrote: > > > This is inaccurate (Earth is not a sphere). > > How accurate does your input have to be for that to be a significant? > I.e. if you're calculating the distance between two cities, and each > city is 5 miles wide, the distance is +/- 10 miles depending on where in > the two cities you decide to get the coordinates from. So if the error > in the formula is 2 miles, it's less than the inaccuracy in the input, > so the formula should be good enough. No one said that these calculations are only for distances between large cities. Anyway, the error induced by assuming spherical Earth can be up to 1%, which is not insignificant when the distances are on the order of magnitude of many hundreds of kilometers (3757 km and 4301 km values were cited by the OP).