should transit maps be geographical or abstract?

In some agencies, it goes without saying that transit maps should be geographically accurate.  Many agencies follow San Francisco Muni in superimposing transit lines on a detailed map of the city:

Sf frag

But research out of MIT suggests that we really need to see network structure, and that requires a degree of abstraction:

By putting alternate versions of the New York and Boston subway maps through the computer model, the researchers showed that abstract versions of the maps (as opposed to geographically accurate versions) were more likely to be easily understood in a single, passing glance. 

Here's their example:

Geographical accuracy obscures network structure.  Purely geographic maps show where service is but not how it works.  

This is why a number of best practice agencies publish both kinds of maps, sometimes even presenting them side by side.  The geographic map helps you locate yourself and points of interest in the city, but you need the structure map to understand how the system works.

All this is even more urgently true for bus network maps, where complexity can be crushing to the user.  When we streamline maps to highlight key distinctions of usefulness such as frequency, we often have to compromise on geographic detail.  Obviously the best maps fuse elements of the two, but you can always find the tradeoff in action.  The new Washington DC transit maps, for example, highlight frequency (and show all operators' services together) but there's a limit to the number of points of interst you can highlight when keeping the structure clear:  

Dc slice


11 Responses to should transit maps be geographical or abstract?

  1. James Bunting November 7, 2013 at 11:32 am #

    I think that one of the most important points to consider is clarity. If you have a network that is relatively straightforward then geographical accuracy is not necessarily important. Once the network grows and/or becomes complicated then geographical accuracy becomes more important.
    An example of this, and one on which a major decision will need to be taken sooner rather than later, is the London Underground pocket map. This is based on the famous design by Harry Beck in 1933. With the addition of the Docklands Light Railway, London Overground and the Emirates Airline the diagram is becoming particularly crowded and is loosing clarity. Transport for London will soon be taking over some, but by no means all, rail services currently provided by National Rail franchisees in the Greater London area. Their policy of adding London Overground (their brand for such services)means that the diagram will cease to be fit for purpose and they will have to stop publishing this world famous pocket diagram. Indeed, some argue that we have already reached that point.
    ATOC, the organisation representing the different rail franchises, publish a large diagram covering all of the networks provided by the different franchisees, but Transport for London choose to only show the services for which they are responsible.
    The naming of stations, and the fact that they are on lines of different companies built over many years, means that people can get very confused and end up taking lengthy journeys because there is no geographical contact.
    In the past we have had geographical maps of the Underground as well as diagrams and I think we shall need to have them again very soon.

  2. BBnet3000 November 7, 2013 at 12:12 pm #

    I prefer something in the middle for most complicated urban networks, though i like more abstract for commuter rail.
    The Kickmap is a great example of a hybrid approach for New York City. I find it much easier to read than either the Vignelli (fairly incomprehensible to me, other than that I now know the system/city well) or the current map (which can take a few minutes to figure out a complicated routing).
    I think surface transit tends to be harder to do abstractly than subways, etc. Its quite a dense network in most cities and the specific street it runs on is very important. San Francisco of course exacerbates this with its complicated routes with lots of turns.

  3. Matthew November 7, 2013 at 2:57 pm #

    I’ve tried to highlight the structure of the Boston bus network with a kind of semi-abstract map
    instead of showing the streets where you can pick up the bus, I assume that you’re starting off in one of Boston’s many “squares” and looking to hop to another one.

  4. Simon V November 8, 2013 at 7:14 am #

    I personally prefer the type of bus maps that one can find in Japan. Highly abstract (some don’t even have roads on them, then again, most roads don’t even have names), color-coded, and every stop is named, and announced in the bus. So when you have to go somewhere, you only need to know the name of the stop you’re going to, hop on the right bus and wait for the name of the stop to be announced. Japanese treat their buses like trains in many regards (distance-based fares, stop announcement and display, etc…) even if they’re stuck in traffic.
    Then again, Japan is not so much TOD as WOD (Walking Oriented Development) with transit (especially trains) allowing people to travel from one walk-friendly neighborhood to the other. Thinking about it, a city that requires you to take a bus to go anywhere is not that much better than one that requires you to take a car to go anywhere.

  5. Jeff D November 8, 2013 at 9:50 am #

    Jarrett, says “purely geographic maps show where service is but not how it works”. I would add that geographic maps show people how to get around the city (or town), but schematized diagrams show people how to get around the transit system.
    Locals usually have seen and used enough road maps that they have a rough geographic plan of the city in their heads, so if they are planning a trip on transit, having only schematic diagrams that do not match that geographic accuracy can confuse them. On the other hand, good schematized diagrams are distorted with the specific goal of making them easier to follow, but sacrifice the geographic accuracy in order to do it. I agree with Jarrett that both are needed, for different kinds of users or different trip-planning tasks. Geographic maps can help you find what stop or route you need to take; schematic diagrams can help you navigate the network for your starting point to your destination.
    Like geographically accurate maps, good schematic diagrams may also end up being internalized, especially by newcomers to the city, or by locals who have grown up with it. If it’s the only transit map format available, this can work to users’ disadvantage, such as London’s famous Queensway/Bayswater example (with entrances maybe 100 metres apart, but the schematic diagram makes it look like the best route between them involves changing trains at Notting Hill Gate). More support for the viewpoint that both geographic and schematic versions are helpful.

  6. Max Roberts November 9, 2013 at 2:06 am #

    “Purely geographic maps show where service is but not how it works.”
    I was saying that in August, for example here:
    Also say it in my book on transit map design, “Underground Maps Unravelled”

  7. Robert Wightman November 9, 2013 at 7:23 am #

    With Grid base systems for smaller jurisdictions A true geographical map could be helpful, but for larger areas it puts too much information to be easily read. In the European cities that I have been in this past month there is nothing approaching a grid and streets change names every couple of blocks or just end. A map of Milan looks like a half eaten plate of spaghetti. As someone said naming the squares or Piazzas would be helpful.
    In a city with one way streets and a lot of overlapping routes it is important to have the names of the different streets shown so you know where to catch the bus. No one system is perfect for all needs so choose the one that is best for your area. There might also be an argument about having a simplified map for locals who know where things are and just need a map to figure out which route to take.

  8. Kyle Zheng November 11, 2013 at 6:05 am #

    I don’t think there’s a black and white contrast between graphical and abstract, as we saw with the Washington Subway Map competition. There’s also one dimension missing, which is frequency. i.e. Maps need to portray not only where routes run, but also how frequently they run. This was partly accomplished with the FTN, but the map still showed too much graphical detail.
    So I decided to experiment with one end of the scale. I produced what I called a “Transit Network Skeleton”.
    Basically, the transit network of Burnaby (a city adjacent to Vancouver) is simplified into black and white lines with line width showing frequency. Therefore, buses with significant frequency would be wider. In addition, all lines are streamlined to look as straight & basic as possible, with routes have large headways eliminated from the map altogether.
    Obviously these wouldn’t serve as useful transit maps per-se, but are fairly good at depicting the true structure of a network.

  9. Andre Lot November 11, 2013 at 6:13 am #

    Appropriate maps depend on the layout of the city.
    This is the most recent schematic map for ATM. It includes the local stations of suburban trains (S-lines) as well
    As the map stands, it does a terrible job on informing passengers about best connections due to geographical compression.

  10. November 15, 2013 at 10:27 pm #

    The MIT study you cite seems authoritative, but I’m also surprised that you don’t reference Harry Beck’s Underground map–or the NYC Subway map that Alessandro Vignelli designed, based on Beck’s model (for a short discussion of both, see my post
    It’s interesting that the abstract/schematic maps are more conducive to underground representations, to be sure; there is a resistance, I think, to representing much that lies above ground in a similarly schematic form. But the innovation of the “circuit” model of map that Beck designed has an amazing conceptual fluidity, as I note in the post, in part no doubt since it is so extremely persuasive.
    Thanks for suggesting I look at your blog when we met at the Stamen Happy Hour.

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