# From where are they measuring distance from a city? **URL:** \ **Category:** Factual Questions\ **Created:** [March 18, 2018, 12:13pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772 "2018-03-18T12:13:58Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [March 18, 2018, 11:16pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/21 "2018-03-18T23:16:33Z")
From the [Manual on Uniform Traffic Control Devices](https://mutcd.fhwa.dot.gov/HTM/2003r1/part2/part2d2.htm#section2D36): “The distance shown should be selected on a case-by-case basis by the jurisdiction that owns the road or by statewide policy. A well-defined central area or central business district should be used where one exists. In other cases, the layout of the community should be considered in relation to the highway being signed and the decision based on where it appears that most drivers would feel that they are in the center of the community in question.” In short, there’s no one answer. It’s not always city hall. It’s not always the central post office. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 18, 2018, 11:30pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/22 "2018-03-18T23:30:39Z")
> [@guizot](#): > > Right. As an ex-taxi driver in L.A., I thought about that. We had to very familiar with the intersection of 1st and Main, because that’s “ground zero” for the address numbering system of streets, which can be E., W., N. or S. from there. > > But as **MikeS** says, some cities may not have such a point, or Google chooses something different. > > My question for journalists, however, is this: If you use an online map system, do you just use the driving distance, or the the geodesic distance? The location of the shooting in the OP is actually 38 miles from 1st and Main in L.A. in terms of geodesic distance, but 43 miles driving. When you say “about 40 miles,” it doesn’t matter. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [March 18, 2018, 11:31pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/23 "2018-03-18T23:31:44Z")
> [@GESancMan](#): > > Burnside is the street that divides “north” and “south” in the cartographic sense. There’s NW/SW 6th and NE/SE 6th, on either side of the Willamette River, and neither has anything remarkable at its intersection with Burnside. The Willamette divides “west” and “east,” maybe Google doesn’t want to give coordinates in the middle of the Burnside Bridge? I got nothin’. It is Sixth & West Burnside. Because that is near the heart of town. Sixth is a major business corridor through downtown. Still odd, but vaguely logical. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [March 18, 2018, 11:31pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/24 "2018-03-18T23:31:46Z")
For London, it’s Charing Cross. It is named after the Eleanor cross that stood on the site, in what was once the hamlet of Charing. The site of the cross has been occupied since 1675 by an equestrian statue of King Charles I and a Victorian replica of the medieval cross, the Queen Eleanor Memorial Cross, was erected a short distance to the east outside the railway station. The Eleanor Cross was one of the twelve ornate crosses built by King Edward I in the 13/14th century at the places the places where the body of his beloved wife Eleanor of Castile was stopped overnight on its way to London from Lincoln where she died. Her tomb is in Westminster Abbey. [![](https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Charing_Cross_railway_station.jpg/800px-Charing_Cross_railway_station.jpg) ](https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Charing_Cross_railway_station.jpg/800px-Charing_Cross_railway_station.jpg) ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [March 18, 2018, 11:35pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/25 "2018-03-18T23:35:51Z")
Wait, I’m only an American, but wasn’t Eleanor of Aquitaine married to Henry II? ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [March 19, 2018, 12:02am UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/26 "2018-03-19T00:02:45Z")
> [@Dewey\_Finn](#): > > Wait, I’m only an American, but wasn’t Eleanor of Aquitaine married to Henry II? Apparently the [Eleanor Crosses](http://en.wikipedia.org/wiki/Eleanor_cross) were put up in honor of Eleanor of Castille, queen of Ed-1. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [March 19, 2018, 12:03am UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/27 "2018-03-19T00:03:36Z")
> [@pulykamell](#): > > When you say “about 40 miles,” it doesn’t matter. In this case, obviously, but I’m still curious, because with other locations, I think it does matter how the distance is characterized. For example, Mt. Wilson, which is covered with snow right now, is 16 miles from downtown L.A. – but it’s a 32-mile drive. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [March 19, 2018, 12:13am UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/28 "2018-03-19T00:13:28Z")
> [@Chronos](#): > > A polygon centroid might not always be the best choice. Imagine, for instance, a coastal city in the shape of a semicircle (the other half of the circle, of course, being out over the water). The logical center of such a city is the center of the circle, but the centroid is going to be somewhere further inland. Yep. Or say the polygon is shaped like a banana, or flag and flag pole. There are options to keep the centroid within the polygon. Not quite sure what you would do for a city by the sea. The water would just be another polygon though (in a different layer/dataset that could be analyzed. GIS is really spatial analysis). I have been in GIS for 30 years. Before it was called GIS. It used to be called AM/FM - Automated Mapping and Facilities Management. I don’t pretend to understand the algorithm used. [side note]At the first computer mapping company I worked for, we had AM/FM awards. I saw the plaques, but did not look too close. I always wondered what arm of our business was in radio.[s/n] ---
**Author:** ![DavidwithanR](https://avatars.discourse-cdn.com/v4/letter/d/3bc359/32.png) [@DavidwithanR](https://boards.straightdope.com/u/DavidwithanR)\ **Post date:** [March 19, 2018, 8:13am UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/29 "2018-03-19T08:13:21Z")
My answer (which could be viewed as a voice of sanity, or a cop-out, or anything else) is that in the situations being described it doesn’t matter one bit - people want to know which place you mean, and that’s all. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [March 19, 2018, 11:33am UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/30 "2018-03-19T11:33:12Z")
When I was very young and lived in unincorporated parts of Santa Clara County, California, I was told that house numbers reflected distance to a main post office. I supposed that an address like 14843 Whatever Lane, meant that the house was 14.843 miles from the post office (or perhaps the scaling was different). If Whatever Lane runs perpendicular to the line to post office, then a house might have the same number as its neighbors. but that could be fudged. Do all map/distance websites use the same zero points for cities? I played at [http://www.distancebetweencities.us](http://www.distancebetweencities.us) just now and discover - the zero point for San Jose, Calif. is the City Hall near 5th and Santa Clara streets. - the zero point for San Francisco is the corner of Market and Van Ness (about ⅓ mile south of City Hall), as already mentioned. - the zero point for New York City is City Hall (near entrance to Brooklyn Bridge). - the zero point for London is near Trafalgar Square. - the zero point for Paris is near the Post Office near Hotel de Ville, about ⅓ mile north of Notre Dame Cathedral. - the zero point for Bangkok is Democracy Monument (near Khao San Road!) - the zero point for Nahkon Sawan is the V-Square shopping center at, arguably, the city’s majorest traffic intersection. - the zero point for Chiang Mai is the Tha Pae gate (just a tourist nexus, but which I’ve always thought of as central!) ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 19, 2018, 11:48am UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/31 "2018-03-19T11:48:37Z")
> [@guizot](#): > > In this case, obviously, but I’m still curious, because with other locations, I think it does matter how the distance is characterized. For example, Mt. Wilson, which is covered with snow right now, is 16 miles from downtown L.A. – but it’s a 32-mile drive. I think this would vary depending on journalist and editor. My inclination would be to go by “as the crow flies” distances, but if it’s relevant to the story, maybe say “30-mile drive.” If someone put down “20 miles away” or “30 miles away,” I doubt any editor would really notice the difference in distance or particularly care if the exact distance has no relevance to the story. Like I said, when I was in the industry, there was no standardization that I’m aware of that dealt with this type of issue. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [March 19, 2018, 12:16pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/32 "2018-03-19T12:16:29Z")
> [@boytyperanma](#): > > Google hasn’t made their criteria public, so I expect it’s more complicated than simply choosing a center point. If they were doing something as simple as the geographical center or post office, they wouldn’t have much reason to be secretive. > > I expect it’s something along the lines of a calculated center based on users final destinations. > [@bob\_2](#): > > For London, it’s Charing Cross. It’s possibly calculated but there has to be some room for hard-coding because I just tried Google maps directions to London and it indeed is Charing Cross. ---
**Author:** ![Banksiaman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/banksiaman/32/3334_2.png) [@Banksiaman](https://boards.straightdope.com/u/Banksiaman)\ **Post date:** [March 19, 2018, 1:43pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/33 "2018-03-19T13:43:44Z")
Exactly 200 years ago in 1818 a sandstone [obelisk](http://monumentaustralia.org.au/themes/landscape/settlement/display/23313-the-obelisk)was erected near the head of Sydney Cove, in Sydney [NSW, Australia, Earth] as the point from which all road measurements would be calculated. It still serves that function, but the Google pin drops its point at the MLC Centre, 622 metres away. Purely coincidentally the MLC Centre is where the US Consulate is located. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [March 19, 2018, 1:52pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/34 "2018-03-19T13:52:26Z")
> [@septimus](#): > > Do all map/distance websites use the same zero points for cities? Apparently not. I compared g-maps to a-maps and found that what each identified as a given city did not match the other. a-maps always finds something similar to city hall as the centerpoint, whereas g-maps uses some other but similar criterion. In the case of London, one is Trafalgar Square while the other is Parliament Square. The difference in some cities can exceed a km (look at what g-maps says is Madison Wisconsin), others half a block. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [March 19, 2018, 2:00pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/35 "2018-03-19T14:00:53Z")
> [@Banksiaman](#): > > Exactly 200 years ago in 1818 a sandstone [obelisk](http://monumentaustralia.org.au/themes/landscape/settlement/display/23313-the-obelisk)was erected near the head of Sydney Cove, in Sydney [NSW, Australia, Earth] as the point from which all road measurements would be calculated. It still serves that function, but the Google pin drops its point at the MLC Centre, 622 metres away. Purely coincidentally the MLC Centre is where the US Consulate is located. For Charing Cross it has you go to Trafalgar Square and then, even if your directions are by car, it still has a grey dotted path at the end of your journey that takes you to the equestrian statue 100 feet away. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [March 19, 2018, 2:11pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/36 "2018-03-19T14:11:04Z")
> [@septimus](#): > > - the zero point for London is near Trafalgar Square. > [@bob\_2](#): > > For London, it’s Charing Cross. There may be some disagreement site-to-site, but I’ll call this a wash. The Charing Cross Underground station is in Trafalgar Square. ---
**Author:** ![butler1850](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@butler1850](https://boards.straightdope.com/u/butler1850)\ **Post date:** [March 20, 2018, 1:40pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/37 "2018-03-20T13:40:01Z")
> [@septimus](#): > > I played at [http://www.distancebetweencities.us](http://www.distancebetweencities.us) just now and discover I grew up in a town with a train station, and now live in a different town that also once had a station. This site uses the railway stations as the “center” of town, though I’d have defined it in both cases as at least a hundred yards away. Certainly “close enough” though. For any straight line measurement that is going to have a base distance in miles, a couple of hundred feet for the endpoints is noise value once you get out a bit. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [March 20, 2018, 2:28pm UTC](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772/38 "2018-03-20T14:28:26Z")
> [@mhendo](#): > > In London, for example, there’s actually a marker in Trafalgar Square showing the exact spot; you can see it in [this BBC article](http://www.bbc.com/news/uk-england-35562786). I was pleased to see that the old signpost being used as a swing by the children in the photo at the top is [still there](https://www.google.co.uk/maps/@51.2689447,-2.586644,3a,15y,5.06h,84.43t/data=!3m6!1e1!3m4!1s9T2jVXaXXNzqPcbO1C4EVA!2e0!7i13312!8i6656?hl=en) (at least it was when the Street View car went by). Looking a bit the worse for wear now, though. [Previous page](https://boards.straightdope.com/t/from-where-are-they-measuring-distance-from-a-city/810772.md?page=1)