Posts about Maps

Rob Pitingolo has done a lot of research on which places have more or fewer people with college degrees. DC has the fourth most college degrees per square mile of any city in the nation, but that doesn't apply everywhere in the region or everywhere in DC.

Rob created these maps that show the locations of people with and without college degrees aged 25 and over.

There seems to be a fair amount of mixing in Virginia, but in DC and Maryland, the divide is starker. East of the Anacostia, blue dots are very few; west of Rock Creek and in the central city, they overwhelm the pink dots.

A lot of news stories talk about the DC region in terms of the division between black and white. The city's history of racial segregation has left a legacy of educational and socioeconomic inequality. As a result, many commentators use race as a simplistic shorthand for conflicts that are really about college educated versus not, or wealthy versus poor, or young versus old.

Race is immutable, but other characteristics are not. If our divisions are really about black versus white, they're not going to change unless some people move out of the city, and that's not what we want to happen. But education levels can change, and it's good for everyone if we can help all people in our region access better education.

My recently completed master's paper analyzes the factors behind the number of trips at different Capital Bikeshare stations. I created a regression of trips in October 2011 that began at stations in the District. After controlling for 14 variables, the analysis concludes that 5 key factors primarily determine a station's usage:

• The population aged 20-39
• The level of non-white population
• The retail density, using alcohol licenses as a proxy
• Whether Metrorail stations are nearby
• The distance from the center of the CaBi system

I measured each variable based on what's within a ¼-mile walk of each station. With that information, I created a "suitability map," above. For any spot in DC, it projects how much ridership a station would get if DC placed one there. You can also download the KML file to view the analysis in Google Earth.

The map shows that as you get farther from the main activity centers in central DC, there's a dramatic drop-off in station demand. Approximately 13% of Capital Bikeshare stations, as of March 2012, are located in areas where we would expect fewer than 18 trips a day. The actual usage data shows that a significant number of these stations at the edge of the system have even fewer trips.

There are equity reasons to place stations outside the core; policymakers want to make sure that money spent on Capital Bikeshare benefits more than just those who live and work in central areas, and it builds political support from councilmembers representing wards farther away. However, there are multiple areas around the District that are under-served by bikeshare today, yet highly suitable under the analysis.

Planners and policymakers should consider these areas as they build out and tweak the system in the coming years. The figure below shows the coverage gaps by overlaying the existing bikeshare stations and the suitability map.

Suitability gaps in the Capital Bikeshare system.

What can we conclude from this? The Washington region and other cities should consider the following issues when they plan and expand their systems:

Distance from the center matters. This variable accounts for 60% of the variation among station usage, by far the most of any factor. This matches a principle known as the "gravity model" in transportation planning, which predicts more trips between closer locations. Capital Bikeshare's pricing structure also encourages shorter trips by charging for using a bike over 30 minutes, which strengthens this factor.

Carefully weigh goals of equity and coverage against ridership. It's very important to provide active, multi-modal transportation options to low-income and minority communities, and this study does not dispute that. That being said, it is important to carefully assess the tradeoffs among various objectives, especially in light of the relative costs of providing other mobility options for individuals of lower socioeconomic status.

Suburbanization of bikeshare has opportunities and pitfalls. The prospect of a region-wide bicycle sharing system in the nation's capital is an alluring one to advocates. It is easy to imagine a robust, polycentric system around dense nodes like Alexandria, Arlington, Bethesda, College Park, and Silver Spring.

However, some facts could temper that enthusiasm. Even some relatively close-in stations in the District have very low usage. Nearly 40 of the 97 stations in operation during October 2011 experienced 15 or fewer trips a day. Similarly, the densest parts of Arlington, with 18 stations during the same period, had 15% of stations system-wide but just 5% of trips.

To successfully expand bikeshare into the suburbs, planners need to choose station locations wisely, and elected officials need to invest enough to create a critical mass of stations early on. If we rush to build an inadequate suburban system, then it will likley not meet expectations and could act to blunt public support for the program, precluding a more economically sustainable system later on.

Stations can easily move as we learn more. Within a matter of hours, bikeshare operators can load stations on a truck and redistribute them to more suitable locations. While Capital Bikeshare operates year round, colder cities like Montreal and Boston take their stations away each winter. Planners there use the spring launch of the system to refine the location of their stations based on station performance the previous year. Capital Bikeshare should schedule an annual station redistribution.

Promote open bicycle sharing data. Having this data available to graduate students and anyone else promotes transparency, scholarship, and innovation. Bicycle sharing systems are proliferating rapidly, which is very encouraging, but few systems nationwide release trip data.

For instance, despite $4.5 million in grants from public sources ($3 million from the Federal Transit Administration), data from Boston's Hubway remains proprietary because of a private sponsorship agreement with New Balance. New York also hopes to fully fund its system with private dollars, which creates a danger that the same may happen there.

Like other North American cities, DC relied on international practices to plan its original system. Now, with an ample stream of data and more than $13 million in public funding committed to the regional system, it is time to strategically reassess station locations to ensure that bike sharing remains viable for the long term, as a true transportation investment.

The comments generally fell into 2 categories: questions about the definitions, and malls that should be added to the map.

Definitions

For the purposes of this map, an "enclosed mall" is defined as a shopping center in which there is a row of small retail shops that are primarily accessed by pedestrians via an interior walkway. The two key components are small shops and an interior walkway.

Buildings with interior spaces that consist primarily of large format retailers (such as the Pentagon Centre or DCUSA) are not malls for this purpose. Neither are spaces that are primarily food courts. Basically, to qualify as a mall for this map, a shopping center should have a space that looks generally like this.

Additions and subtractions

This second draft includes the following malls that were left out of the first: La Promenade (DC), Waterside (DC), Free State (Bowie), Livingston (Ft Washington), Chevy Chase Pavilion (DC), National Place (DC), Beacon Mall (Mount Vernon), 2000 Pennsylvania Ave (DC), New Carrollton Mall (New Carrollton), Centre at Forestville (Forestville), Rolling Valley Mall (Burke).

The only mall I subtracted from the original map was Virginia Square, which had a department store but apparently never an enclosed row of smaller shops.

I also removed references to "thriving" and "surviving" from the table in the legend, since that was subjective and unclear.

Notable omissions

Shopping centers that could be considered malls but that don't meet the definition I used for this map include DCUSA, Old Post Office Pavilion, Gallery Place, Pentagon Centre, and the terminals at National and Dulles airports. The airports might technically meet the definition, but they're obviously a different animal.

Cross-posted at BeyondDC.

The 31 malls on the map range from small local ones like Fair City in Fairfax, to gargantuan super-regional ones like Tysons Corner. The only requirement to be on the map is that malls contain a common interior hallway lined with several shops.

Some, like Pentagon City, are chugging along as healthily as ever. Others, like Seven Corners Center, have been gone for years. Overall, more than 40% of the dots are red.

The reasons malls have closed vary as much as the malls themselves. Some closed because they were housed in cheap buildings that simply reached the end of their intended lifespans, while others couldn't compete with the mixed-use town center developments that have become common in recent years.

Geography seems to be unimportant in whether a mall lives or dies. Red dots permeate all corners of the map, regardless of the wealth of the jurisdiction.

One thing that does seem to make a difference is size. Larger malls that draw from a wider area generally seem more likely to thrive than smaller ones. As the years go by and even more green dots turn to red, it's likely the last hold outs will be the biggest and most famous.

Is this map comprehensive? Did I miss any malls? Let me know in the comments.

Cross-posted at BeyondDC.

Lance Wyman, the man who designed the original iconic map that has served the system for almost four decades, came back to revise this map. The new map, which shows the peak hour service patterns Metro has dubbed "Rush Plus," keeps many of the same elements as the original.

But there are some changes, both subtle and otherwise, since the last version in October of last year.

The National Mall is darker and labeled. The final version of the map shows the National Mall and West Potomac Park (and the White House grounds) in a darker shade of green than the other parks shown on the map. This subtle change might make it clearer to visitors which stations are close to the Mall.

Station names have changed. The new map also introduces a few name changes which the WMATA Board voted on them several months ago. At least one station is getting a longer name: Navy Yard-Ballpark. But this map shows the first effort ever at attempting to shorten names. Many stations will be getting subtitles, and the New York Avenue station will be losing a few characters.

Many other small changes. Metro fixed a few errors in the draft, like moving the bend in the Red Line back to between Van Ness and Tenleytown, and putting the dots on the eastern branch of the Blue and Orange Lines in the center of the lines where they belong. The transfer station symbol for the Silver Line at East Falls Church is gone, and the Red Line stations in Maryland on the Shady Grove side have gotten more spacing.

Below, you can see an image overlaying the October draft atop the final version. In addition to the changes listed above, you can see some shifts in some map elements along with other changes.

Eagle-eyed readers might notice that some of the station names are still closer to their lines than others, and the parking symbols somewhat inconsistently align with either the top or bottom of the text.

More changes are coming

This map will only serve Metro for about 2 years. Another revision will happen when the Silver Line opens in late 2013 or early 2014.

Metro elected not to show the yet-to-open Silver Line running through downtown with the Blue and Orange Lines because it might confuse visitors. Instead, the new map will only show the Silver Line west of its junction with the Orange Line.

But since the Silver Line will run all the way to Stadium-Armory on the east side of the city, Metro will need to redesign the map to add it to the Blue/Orange trunk line. Lance Wyman has already created a draft of that map, but it does leave hope that any bugs with this map can be fixed in the 2014 version.

Consider showing short turns

The initial draft released in September used small dots to show stations where trains sometimes turn, such as Silver Spring and Mount Vernon Square. The October version took these out.

Left: The first draft of the revised map. Right: The final version.

I've felt that WMATA should do more to highlight stations on the map that appear regularly on train destination signs. Customers unfamiliar with the system need to be able to quickly identify the station on the destination sign so they know whether or not the train will take them where they need to go.

Perhaps the forthcoming next version can find a way to show this information that enlightens rather than confuses riders.

What do you like about the Rush Plus map? What would you change?

Here's southeast Georgetown. Note the wooden bridge for K St. across Rock Creek, the factories and lumber yards on the water, and the fact Virginia Ave. used to go across the waterfront.

Here's southwest Georgetown. What's notable about this map is the streams that ran through Georgetown at this point, as represented by the black lines meandering through the neighborhood.

Here's northeast Georgetown. Notice that Q St. wasn't constructed yet, and Dumbarton House hadn't been moved yet. Plus, there was a giant streetcar facility on P St. (not to mention homes in what is now Rose Park).

Here's central Georgetown. What's notable here is that, as I discovered Monday, the addresses of homes north of Volta were different. And that's because Volta Place was Q St., Q St. was R St., Dent Place west of Wisconsin was S St. (east of Wisconsin it was Irving Place), Reservoir was T St. and R St. was U St. Oh and Wisconsin was called 32nd St. and 32nd St. was called Valley St.

Finally, here's northwest Georgetown. Note that Volta Park used to be the Presbyterian Burial Grounds, and that the weird Tudor style home on 33rd between Volta and Q was the Presbyterian church.

30-minute isochrone from the White House. Image from Mapnificent.

He encouraged cities to move away from the historic North American penchant for putting a bus stop at nearly every corner (something not done in the rest of the world), and expect riders to walk a little more so that service is faster for everyone. Shortening trip times reduces the cost of providing service, which usually means that more service can be provided. It also encourages more people to ride, because it increases the area of the isochrone.

Transit routes that deviate off a direct path to serve poorly-located shopping centers, housing cul-de-sacs, and insular complexes, inconvenience through-riders and make transit less attractive, he said. Anything not built "on the way" is essentially saying, "I only want as much transit service as I alone can support," because those destinations can't be pooled with any other destinations. Once urban areas have taken this built form, it becomes expensive to provide service to them.

He ripped into WMATA's Metrobus map, pointing out that almost every route is shown in red, regardless of how often it runs. That's not helpful, he says, because it's like a roadmap "which doesn't differentiate between a highway and a gravel road."

Section of the DC Metrobus map. Image from WMATA.

Maps like this, which Walker laments are all too common amongst US transit systems, put the onus on the rider to first figure out what routes get them to where they want to go, then consult a complicated schedule to find out how often it runs.

Instead, he said, the map's design should make it as easy as possible on the rider by displaying routes based on frequency. Routes with the most frequent and round-the-clock service "should scream out at you," he insisted. For example, putting routes in a different color would let riders know at a glance if they could easily jump on board and not bother with a timetable.

Poor map design and inscrutable signpost information cost more than just riders. In some cities, it's become so frustrating that officials have thrown up their hands and turned to another form of transit altogether. Walker finds that unconscionable: cities shouldn't build streetcars or new bus systems simply because the existing system is incomprehensible. He pointed to the DC Circulator as a prime example of unnecessary duplication that squanders public resources that would be better spent making the most-used Metrobus routes more frequent and user-friendly.

His point about circulators is instructive for Tysons Corner, where five are planned. Walker says when good bus service is already there, adding circulators can be redundant and wasteful. In Canberra, Australia, planners faced with a similar situation saved lots of money by choosing simply to rebrand a section where many existing bus lines converged as one cohesive service (the "Green Line") with clock-face regularity.

He acknowledged that streetcars do tend to drive economic development because of their perceived permanence and attractiveness compared to buses. But he urged planners to remember that 50 years from now, any economic development potential today will be distant history, but the travel time riders gain from a bus which can navigate around obstacles will endure. He further cautioned against thinking of laying rails as signifying permanence, since most of DC's original streetcar tracks have been paved over.

Above all, Walker emphasized, transit agencies and the governments that fund them should see their job as enhancing freedom by making as much of the region as possible accessible by frequent, reliable service. The other things transit does, such as spurring economic development, providing jobs, protecting the environment and enhancing social equity, are all secondary to this primary purpose of transit.

If you missed Jarrett last week, you can watch his presentation to the Montgomery County Planning Department, below:

In the DC region, travelers often can choose among many transit routes and modes. To help travelers, maps and apps display a variety of information, like the routes in a geographically accurate or diagram form, vehicle arrival times or positions, and more.

It would be extremely useful to transit users, transit agencies, and app designers to understand exactly what displayed information is really helping travelers make better choices. Fortunately, Hartwig Hochmair, now a professor at the University of Florida, designed a clever web experiment (PDF) that helps answer this very question.

For simplicity, let's assume that travelers want to find the fastest route. Not all do; some prefer a trip where they can get a seat, or prefer the smooth ride of rails over a bus. But many do want to minimize overall travel time.

However, it's not always simple to figure out the fastest route. Maps can't contain all the information to decide this perfectly, and the rider usually has limited time to make a choice. So travelers quickly pick a subset of information, one of several "proxy variables," and use it to choose a route, such as:

• Shortest total distance
  
• Fewest number of stops traveled
  
• Most linear route, heading straight toward the destination
  
• Fewest transfers, for less total waiting time
  
• Most transfer options at each station, allowing a switch to the first train in the direction of the destination

Do people choose different proxy criteria depending on how a map displays the information? Hochmair asked experiment participants to plan trips on the metro system in Vienna, Austria. That system has many interconnected lines, giving riders many choices among complex routes.

The geographic map of the Vienna U- and S-Bahn used in the experiment.

Hochmair's participants saw 5 different displays:

• A geographically accurate map
  
• A diagrammatic map based on the official map
  
• A map showing the real-time positions of vehicles
  
• A map with service frequencies, showing the time between arrivals per line
  
• A map showing the next departure time for all lines from the starting point

He tested 35 people with varying levels of Vienna metro experience by giving them 40 route-finding problems apiece. Based on the routes chosen, he was able to use a statistical model to conclude that while people used distance information in every map, the different maps also caused people to use different proxy criteria for planning their route:

• The geographically accurate map led people to pay attention to the number of stops traveled.
  
• The diagrammatic map, and the map showing next departures, led people to pay more attention to the total number of transfers.
  
• The map showing service frequencies caused people to pay more attention to the number of transfer options at each stop.

Which of these maps is the best to help people minimize travel time? For the complex trips in Hochmair's study, inexperienced users benefited most from having service frequencies. Meanwhile, for experienced users, service frequencies also turned out to be best, with vehicle positions second.

The study still concludes that a map with real-time information is better than a plain map. But the usefulness of real-time information decreases as the number of transfers increases, because a traveler doesn't know exactly when they will arrive at each transfer point. For trips with more transfers, most travelers would be better off following a route where service is most frequent.

Most transit maps do not contain this information. Bus maps like WMATA's standard map (PDF), for instance, show every line the same size and weight whether it runs once an hour or every 3-5 minutes. WMATA's planning department did put together a map of routes with buses more frequent than 4 times per hour, and the agency should actively promote this clear and helpful tool.

Central DC section of 15-minute Metrobus map. Click for full map. Image from WMATA.

A final lesson of this study is that, between different traveler preferences and the different ways travelers use information, agencies and app designers must keep the needs of different users in mind. But all can take fairly low-cost steps to help riders by making service frequency information more prominent.

GGW contributor and urban photographer MV Jantzen emulated the Travel Time Tube Map, which shows the London Tube in the same way. Click on any station on the right side, and the map shifts. Each station still appears in the same direction from the start as in real life, but its distance changes. The longer it takes to get to that station, the farther away it appears.

Transfers also take some time, and an option lets you see what the map would look like if it considered each transfer equivalent to making extra stops. Note that if your screen is not very wide, the list of stations may wrap off the bottom edge; try making your browser window wider or less high to compensate.

Having built an app that could dynamically reposition Metro stations based on an algorithm, Jantzen could add other formulas besides just time and distance. You can press 9 to see the familiar diagrammatic map, 8 to see a diagram that shows routes as straight lines meeting at 90° angles, or 7 to see the lines as a set of concentric circles. Others are even more whimsical, up to a Pac-Man style game played on the map.