good network maps: clear without color?

As I mentioned two days back, the new Spokane, Washington network map [Full PDF], designed by CHK America, is exceptionally clear in presenting the layers of the network so that you can see all of the following at a glance;

  • The network of frequent services, useful to you if you aren't willing to wait long.
  • The network of all all-day services (frequent or not), which is the total network if you're travelling midday.
  • Supplementary express services, mostly peak-only, that are likely to be useful only to the regular peak hour commuter.  These always contain a high degree of complexity, so they must be presented in a way that visually recedes from the rest of the network, so that the all-day network is clearly visible.

The key point is that each layer is never allowed to distract from the ones above it. 

Spokane map Spokane legend

But it has one other important feature that I should mention: If you look closely, you'll see that its content is still there if you copy it to black-and white. Line widths and styles distinguish all the service categories from each other.  The only exception is the distinction between "Shuttles" and "Frequent Routes", both wide lines, and this matters less than it seems because the shuttles are frequent too.

All this is relevant not just because the world is still full of black-and-white photocopiers, but also because of color-blindness.  Matt comments: 

Recently I noticed playing around with Scribus, the Open Source Desktop Publisher ( that "Scribus has a well developed tool, the Color Wheel plug-in, which helps to guide you selecting complementary colors, as well as visualize colors seen by folks with certain kinds of color-blindness.". So turning on an option for the three or four different types of colour-blindness lets you see what the colours look like for someone with each type.

Perhaps there is a chance that in the future a pdf viewer could incorporate something like that, such that bus maps (mostly they're rendered into pdf) and anything else in pdf could be seen as if you were colour-blind. Then the bus companies could experiment and release colourblind friendly maps.

All good, but the simplest solution for color-blindless issues is to design maps so well that the information is all there in line weights and styles, so that the color is supplementary — very, very helpful for those who can see it but not essential.  The Spokane map does this. 

The current Portland map also tries to do this, Portland inner with a different line-weight for each of its four layers.  The four layers are:

  • Light rail:  colored line with black outline.
  • Frequent Bus: heavy solid colored line (and, if you look really closely, a yellow-shaded line number)
  • Basic Bus: slightly thinner colored line.
  • Peak-only: dashed line.

Portland's TriMet uses different colors for different lines, but if you copy it to black-and-white you should still be able to make out these four line weights (though not, of course, the feeble yellow shading of frequent line numbers). 

I agree with many observers that the distinction between frequent bus and basic bus is insufficiently strong on the Portland map, whereas the Spokane map shows this distinction dramatically.  In the past, when I've tried to use the Portland map as an example of clear delineation of network layers, I've been told that the distinction just isn't clear enough, so now I'll use the Spokane map instead.  Still, Portland's intention is clear enough.


13 Responses to good network maps: clear without color?

  1. Ed Sanderson September 13, 2011 at 7:16 pm #

    Some things are difficult to scale up. While the Spokane map is easily read and understood, the Portland map is decidedly not. I invite you and your readers to try to add color-coded bus routes with frequencies to the Chicago metro bus system. As a “easy” starter, here’s a link to the downtown detailed map (estimated area: 2 miles by 2 miles)
    And here’s one for the entire area:
    I read here (I think) a comment from a visitor who didn’t understand why every bus stop didn’t include a system map.
    Well, really Blanche…

  2. Beta Magellan September 13, 2011 at 7:22 pm #

    Actually, I’d say downtown Chicago’s much more difficult due to the amount of interlining, prevalence of two-way pairs and short-haul circulators. Start with the city as a whole and then have a downtown detail.

  3. Ed Sanderson September 13, 2011 at 7:27 pm #

    Sorry, operator error, the first link should have been.

  4. Joe Clark September 13, 2011 at 9:29 pm #

    No, the solution is to use colour combinations proven to work with colour-deficient and -normal subjects. Cindy Brewer put a lot of research into such combinations, which have been published and available for ten years.
    Colour deficiency is not monochromatic vision. Confusion between red and green (often limited to colours of equal intensity) accounts for most of the problem, along with confusion among shades related to red and green (pink, beige, etc.).
    B&W photocopiers are a good reason to make a map legible in monochrome, but please do your research before reiterating folk misunderstandings of colour deficiency.

  5. zefwagner September 14, 2011 at 2:08 pm #

    It is very important to remember that a key to the Spokane map’s ability to use different line widths and to combine lines on shared segments is that it is a schematic diagram map. Portland unfortunately uses a geographic map, which limits the ability to use line weights effectively.
    I have red/green colorblindness, so I am very sensitive to color choice on maps. Certain shades of red and green look the same to me, so it is very annoying when an agency like TriMet chooses to have a Red and Green Line go through the same area. Blue and Purple are also very hard to distinguish, although this is not as much of a problem since purple is rarely used. About 8% of men and 0.5% of women have some degree of colorblindness, so it is important to keep this in mind.

  6. Jarrett September 14, 2011 at 2:43 pm #

    @Joe. Maps that are clear in monochrome are one way to address colorblindness while also addressing other problems of reproduction. I never said or implied that they are the only solution for colorblindness, and approvingly quoted someone saying the opposite.

  7. Jarrett at September 14, 2011 at 3:01 pm #

    Zef.  If you compare the Spokane map with Google Earth, I think you'll find that despite the schematic look it's geographically pretty accurate.  It helps, of course, that the geography is simpler.  In a more crowded city you'd need different notations where many lines crowd together — typically you allow the less frequent lines to disappear under the frequent ones, or greatly reduce their width. 

  8. Steve Lax September 14, 2011 at 5:20 pm #

    A question: Has anyone tried to quantify to what extent a great map helps a system’s ridership to grow?
    (There are obviously many factors that impact system ridership. I don’t even know if it is possible to isolate something like a map in the dynamic environment that is transit usage.)

  9. Duncan September 15, 2011 at 7:19 am #

    As an avid traveller and public transit user who happens to be moderately colourblind, it’s great to see maps that don’t rely on various shades of red/green/brown/orange or blue/purple/violet, etc. You can imagine what it’s like as a tourist trying to read a busmap in a hurry… There are examples of problems with visual communication everywhere of course – I can only barely work out which is the emergency button and which is the information button on my station platform, cos they don’t bother to use icons or words, just red and green paint.
    In reference to Steve Lax’s comment about ridership growth, perhaps two strengths of a highly readable map would be the potential uptake among new residents in an area, and perhaps the number of casual trips taken by infrequent transit users (e.g. “my car’s at the garage, how do I get to meet my friends for lunch?”).

  10. Matt Johnson September 15, 2011 at 7:56 am #

    The thing I like most about Spokane’s map is that when routes overlap, they keep their individual identity, despite being the same color.
    Many transit system maps are just very complex games of “connect the route bullets”. WMATA (Washington DC)’s map is particularly egregious.
    Up until a few years ago, each route family was shown with one of about 10 colors. Sometimes line families of the same color would overlap, but by and large it was easy to tell that the 50’s Line turned here, and the 70s Line went straight.
    About 2 years ago, though, the transit system made a decision I still don’t understand; one that makes their bus map one of the most difficult to understand I’ve ever seen.
    First off, the Metrobus network can only be seen in its entirety using THREE maps. There’s a DC Map, a Maryland Map, and a Virginia Map.
    But the difficult thing is the change. Now all routes that exclusively operate in DC have one color (red). Routes that operate exclusively in Maryland have another color (light blue). Routes that operate exclusively in Virginia have another color (purple). Routes that operate in DC & Maryland are green, while routes that operate in DC and Virginia are orange.
    The result of this is an urban map that is mostly red lines. And to figure out whether the bus runs down your street, you have to find two adjacent route bullets and hope there’s only one red line that connects them. Some neighborhoods are particularly bad, notably Mount Pleasant.
    And how, exactly does the 50s Line differ from the 70s Line? In terms of service, not by much. They’re both arterial bus services on north-south arterials in the Northwest Quadrant. How do they differ on the map?
    Well, the 50s Line is red because it operates exclusively in DC. Of course, the northern end of the 50s Line is at Takoma Station, which is only 1 block from the Maryland state line.
    The 70s Line, on the other hand, operates to Silver Spring station, which is less than a half-mile inside Maryland, so it’s green.
    David Alpert wrote about this when the change happened:

  11. Chris Kay September 15, 2011 at 6:35 pm #

    Translink in Vancouver is long overdue for an updated route map. All the routes are the same color and appearance, with numbers haphazardly scattered about. It took me months to make sense of my local network:

  12. Gil September 17, 2011 at 10:15 pm #

    I guess given it’s size the TTC in Toronto opted for different line types rather than line weights for surface routes (bus/streetcar). Essentially the more filled in the line the more frequent the service. Dotted lines for rush hour service, dashed lines for not-as-frequent or limited service hours (usually no service after 8 or 9PM) and solid lines for frequent service all day. There’s even a variant for express/transit ROW routes which uses a string of diamonds (which doesn’t really show on the .pdf) along the thinking of HOV lanes. All of which works in monochrome.
    The route bullets are spaced apart enough to tell where the routes are going. Thankfully most routes are pretty straightforward. The bullets also indicate direction of travel, branches, express service and there are also bullets for terminus points not at a subway/train station.
    The map also attempts to show neighbouring transit agencies, which for the most part are included in the regional transit pass. (The maps cuts just short of where an external agency can be seen and the limits have been the same since the pass was first implemented in the early 1990’s.) Each agency gets its own colour. Although trying to fit their routes into the TTC’s categories can prove to be a little complicated since they all don’t follow the same criteria.
    The map gets a little cluttered around the edges trying to show all the subway and inter-agency connection points. The latter could easily be placed in a corner and a grid reference used instead.

  13. GClub September 19, 2011 at 11:34 pm #

    Well, this is very good, but what about additional choices we’ve got here? Would you mind publishing one more article about them too? Thanks!