As a fellow cyclist I feel obliged to contribute. A quick check reveals that on my way to work, when I take the shortest route, I get a ratio of 1.26 which is the cube root of 2. On the way home I often take the more scenic square root.
Dominic -----Original Message----- From: B. Thoen [mailto:[EMAIL PROTECTED] Sent: 02 April 2004 15:23 To: MapInfo-L Subject: Re: MI-L weekend question: ratio between like the crow flies and road distance In cities where streets are laid out on a grid, a common approximation for drive times from point A to point B is the "dog-leg" distance divided by speed. In other words, instead of using the striaght-line distance, you use the distance of the sides of the triangle for which the straight-line route is the hypotenuse. If you call the straight-line distance c, and the other two sides of the triangle a and b, then the ratio between a + b to c is (a + b) / sqr(a^2+b^2). If a and b are equal, then this reduces to 2a / sqr(2*a^2) or 2 / sqr(2), or about 1.414. That's pretty close to what you get, so you must be riding about as far in the east-west direction as you do in the north-south direction? - Bill Thoen On Fri, 2 Apr 2004, Christof Kaiser wrote: > Hi out there, > > on my push bike, I have a Garmin Geko 201 mounted on, which is a > wonderful device. Since it does not have street data on it, I am > navigating with compass directions. The remaining distance the unit > returns to reach the desired waypoint is of course like the crow flies. > However, as a cyclist, I stick to the roads. > > Does anybody have experiences which the common ration between the > straight distance and the road distance is? Sure, you are right if you > say: depends on the road network! However, for the region I am living > in ( 7�13'13"E 51�29'18"N ), I experienced a more or less constant > factor around 1.45 . To make it sound more scientific, I ll simply call > it square route(2). > > Does anybody have values for other regions? --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 11252 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 11254
