gis Archives

June 28, 2007

Le Triboro RX

In its 1996 Third Regional Plan, the Regional Plan Association describes a rapid transit line in Brooklyn, Queens, and the Bronx that could be built almost entirely on pre-existing rail rights of way and would connect with at least twenty existing subway lines. The so-called ''Triboro RX'' (''TRX'' for short) presents a unique opportunity to provide mobility and accessibility to New Yorkers living or working within these three boroughs, at a fraction of the cost of most transit projects of similar size. In my part-time internship at the RPA, which ends today, the lion's share of the work I have done has focused on fleshing out the idea of this line.

Working with the singular Jeff Zupan and his former sidekick Alexis Perrotta, I helped to develop a possible alignment for the Triboro RX, and a crude estimate of what levels of initial commuter ridership one could expect to see if it were built. The fruits of this labor can be seen on the web at (including sections on the alignment, our data sources, the demand model, and detailed results). There I describe in detail how the line and its stations are laid out and how we made our estimates. At the end of the day, we can comfortably say that at least 76,000 New Yorkers (including 32,000 diverting from other modes of transportation) would use the Triboro RX to get to and from their jobs every day. This number that is quite competitive with many existing lines, and without ever touching the island of Manhattan.

At the heart of our ability to make this estimate is the Journey-to-Work data published by the census -- counts of commuters between every census tract and every other census tract in the city. Given these flow data, the shape of the subway network with and without the Triboro RX, and a rough model of how people make travel decisions on public transportation, it's not so hard to guess which subway riders would use a new transit line if it were built. Estimating new transit riders is more nuanced, but we did our best with limited resources.

This study of the Triboro RX has, for me, been much more than a semi-traditional transportation modeling exercise. I took it as an opportunity to get intimately familiar with the state of the art in Open Source mapping and GIS software, including PostGIS, GeoServer, and OpenLayers. These pieces represent a full network-enabled stack for, respectively, storing and manipulating, mapping and presenting, and client-side interfacing of spatial data. I don't think they are quite yet usable by the non-hacker, but I wouldn't be doing this work if I didn't think that my computing skills brought something special to the table. That said, I encourage you to check out the following:

Now, it wouldn't be a perfect project to do, for free, when I should be saving money for school, if it didn't also involve getting my hands dirtier than they already do from all the crumbs in my keyboard. It seems absurd to talk about planning a transit line without actually having visited the areas it would connect. Having synced the clocks on my GPS device and digital camera, I twice explored the Triboro RX right-of-way and its environs from Flatbush to Bay Ridge, in Brooklyn. The results are viewable either in Google Earth or directly on the web. What really struck me was the diversity of neighborhoods -- Flatbush, Ocean Parkway, Borough Park, Sunset Park, Bay Ridge -- traversed by the Triboro RX in less than a third of its length. Continuing on, it runs through East New York, Brownsville, Cypress Hills, Middle Village, Jackson Heights, Astoria, and Mott Haven. You could eat your heart out while getting from Brooklyn to the Bronx, skipping "the city" entirely.

Finally, no contemporary New York transportation project is complete if it doesn't some how tie into Congestion Pricing. In terms of providing mass transit to unserved communities in the outer boroughs, methinks this graphic speaks for itself:

PS Please forgive me, I know these maps need legends for the quantitative parts. It's all a big hack, trust me!

PPS The interactive web maps work much better in FireFox than Internet Explorer. Save your soul and get a real browser.

May 7, 2009

Spark it Up

This post is literally 2 years in the making. In the Spring of 2007, Jeff "You Don't Mess With the" Zupan gave me a spreadsheet with the annual 'registrations' (i.e. recorded entries) at each station in the NYC subway system going back to the beginning (1905). At the time, I was heavy into the new open source geo stack, as is reflected in the main piece of work I did at RPA. Hammer in hand, I of course saw this spreadsheet as a bucket of nails.

The result, after much whacking, is, I think, compelling, but you'll have to see for yourself. The general idea it that the history of subway ridership tells a story about the history of a neighborhood that is much richer than the overall trend. An example, below, shows the wild comeback of inner Williamsburg, and how the growth decays at each successive stop away from Manhattan on the L train:

This is somewhat in contrast to the South Bronx, which is yet to see the resurgence in ridership, other than at Yankee Stadium and the Grand Concourse:

The stations around Wall Street tell a totally different story, in which the ups and downs of each dep/recession have more immediate but temporary effects:

My first stab at visualizing this data was a traditional cartographic approach, showing the overall growth from 1977 to 2006 at each station. This told an approximate story at the level of the whole the city, but did not leave much room for detailed exploration. Thanks to geoserver's awesome new(ish) dynamic symbolizers functionality, it was trivial to plot the station-by-station time series sparklines (generated in R of course) onto the interactive online map. (Originally I the plots were produced in Perl and placed onto the map with a Javascript WFS layer, but that is so 2005.)

For all this, I never really felt like this little experiment was ready for an audience. That all changed when OpenGeo put up its Open StreetMap base layer for the web, giving fancy overlays like this one the context they need.


At least 2 people have taken the data I put out there and used it to make some zippier interactive flash apps:

  • The first is very polished, but I think the designer is quite misled in his desire to not plot dots on a map, and thus to plot what looks like a network flow diagram but with totally bogus data
  • The second is a little rougher around the edges, but I'd say is much more honest, and thus useful

Not sure if anyone knows, but I also have GIS files for the subway here:

March 7, 2012

Time for MTA Bus Time

In mid-January, MTA launched MTA Bus Time, its real-time bus tracking and customer information system. It's currently live on Staten Island and the B63 route in Brooklyn, is expanding to the Bronx this year, and will cover the whole city in 2014

It has web map, mobile web, and SMS text interfaces, along with a fully featured, standards-based developer API. Smartphone users can scan the QR code at each stop to be automatically directed to the Bus Time page for that stop.

Particularly compelling to the author is the approach we've taken to delivering this project quickly and inexpensively (for the short and long term). With MTA as the overall systems integrator, we've ensured that the system is constructed using open standards for all interfaces, and open source software licensing when appropriate. And, oh yeah, it runs on Amazon's cloud.

Please, let us know what you think.

Better late than never right? (this post, not the project...)

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