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Brent Palmer

Obviously, the spiral map is all about narrative navigation, whilst most schematic "maps" are a mixture of narrative and spatial.


as much as the DC map distorts scale, it still gives you some idea of where you are in the city - I've once navigated a car through Paris's outskirts using a similar mini map. I find those maps useful, at least once I have an idea of what the physical shape of the city is.

IIRC, there seemed to be agreement in an earlier comment thread that every metro station should feature a standard-projection full system map. If the Metro map does at least retain some semblance to the physical layout of the system (as D.C's does) then you have a lot of an easier time getting oriented on the larger, full-system thing.


Oh noes! The transit death spiral!

Alexander Craghead

The thing to remember is that the purpose of tranist maps -- and in fact most maps -- is data visualization, not representation. Accuracy to geography, topography, and such is (usually) not important or sometimes even relevant at all. While the spiral is funny, it fails because it fails to convey an important piece of data, the relationships between the various routes.

Jarrett at HumanTransit.org

Alexander.  On the contrary!  It very accurately portrays all the connections among the routes!  It's just not interested in the relationship to the city!  For what it its, it's perfectly accurate.

Wai Yip Tung

This is a great demonstration of Topology. Mathematicians will be delighted :)

Andre L.

One aspect concerning structurally-eased maps, when they depart often from geographical positioning of stations and routes, is that they might mislead passengers making connections (transfers).

Indeed, suppose someone is travelling on Washington from Ford Totlen to Rosslyn. Minimizing the number of transfers, there are 3 options:

I. Red Line to Metro Center, change for Blue or Orange Line to Rosslyn

II. Green or Yellow Line to L'Entant Plaza, change for Blue or Orange Lien to Rosslyn

III. Yellow Line to Pentagon, change for Blue Line to Rosslyn.

How should a person without deep knowledge of the system (like frequency of each line, time spent walking on transfer stations) could address such a scenario (which is not uncommon at all in cities with a interconnected, intermingled network of frequent rail service)?

I suppose most people will try to find the "most direct and straightforward route", which would be option I. But the schematized map might betray an user if they bear not much relation to real geographic placements.

Other alternative would be counting the number of stations: option I involves travelling through 10 stations, option II - 14 stations, option III - 10 stations.

In a system like Paris Metro within the most central districts, using the number of stations passed as a proxy for travel time might work, as they are more-or-less evenly (and shortly) spaced, putting the burden of time travel on stopping and embarking/alighting. However, in a place like Washington, that might be not the case at all.

I know the example I gave is somehow overstating a problem, as a frequent traveler would likely learn, empirically, what is the best way to travel between those two stations rapidly (maybe option II has the shortest walking distance on transfer point of the less crowded trains...). Yet, distorted maps might create more serious trouble when one is facing trips on the "compressed" zone, or on schematized bus route maps.

Alon Levy

The main problem with the spiral map is that it doesn't actually show topology. It shows the line-station relations, but not the way the lines intersect. A topologically accurate map should be topologically equivalent not just to the graph of the geographic map, but also to its embedding in two-dimensional space. Put another way, such a map should distinguish between the cruciform configuration in which both lines are straight, and that in which both lines turn 90 degrees at the intersection.


A geographic map won't help you in many cases - it might even deceive you into thinking some path is shorter than another, because your map is "geographically accurate". Consider the case of Manhattan, where the A train is much faster than the 2. Even if you take the local 8th ave train, the speed difference is quite noticeable, still.

In many cases, schematic maps will only really distort suburban areas - where there's only one line anyway. And then just using distances to compare routes might work out fairly well.

On the other hand some schematic maps, through the distortion of areas and omission of some geographic features (like streets), have the space to provide information that is potentially more useful than knowing geographic distances accurately. These can include providing a better sense of the stations (where are the transfers long? Untangling where many lines meet), information on fare zones, etc.


Both are needed. Give the spiral to us transit heads that flip out over the distortion and need a more advanced experience. Keep the geographic map for tourists, but also put a real map next to it. Many Metro stations have the simplified Metro map next to the bus map that actually has a real scale with all the streets and landmarks. Also, hotels hand out more detailed maps that include both geo scale and stylized maps. Folks that still can't read that are just completely lost.

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