November, 2013 Archives

Strava ExplorerStrava, the software used by athletes to track their activities, has a new API available for accessing their data. I looked through it to see if I could do anything quick and interesting with it.

Earlier this year they angered many developers by unplugging their previous API, leaving many third-party apps stranded. My own interest is in seeing how cyclists use the city: which routes are preferred. Unfortunately, the data available in Strava’s v3 API is extremely limited. Most of the API is designed to reveal a selected user’s data, assuming they have specifically granted the program access. But there doesn’t seem to be a way to look at aggregate data.

In fact there seems to be only a single API function which accepts a geographic bounding box as an input. That API, the “segment explorer” returns up to 10 “popular” segments.

I wanted to see how easy it would be to use the API in a little test program. The result, my Strava Explorer, doesn’t really do anything interesting other than prove I can connect to the Strava API. » Continue Reading…

cabitypesNew Capital Bikeshare data sets have been added to the Activity Mapper visualization tool. I started with showing bikein & bikeout totals for each station for a single day in September; the new data sets all look at the entire 3rd quarter of 2013, from July through September. Instead of summarizing subtotals in 5-minute chunks, the new data sets have a subtotal for every day. The 3rd quarter includes the 13 CaBi stations that debuted in Montgomery County at the end of September, but since their traffic is dwarfed by the rest of the system, there is not much to see.

New controls let you customize the display. Use the + and – keys to zoom in or out (clicking will zoom and center). Ctrl+ and Ctrl- increase and decrease the size of the circle. ← and → can control the time sequence by moving backwards or forwards in time, one segment at a time.

The program compares two sets of numbers for each station. Originally, I showed the number of bikeins and bikeouts per station. (CaBi also calls these actions rentals and returns, or un-dock and dock.) A new data set compares subscribers to casual riders. Subscribers buy memberships for a month or a year, while casual riders buy the 1- or 3-day memberships. Another new data set compares “on-time” rides to “late” rides. On-time means the trip took 30 minutes or less. The rides are counted against the station where the trip ended. » Continue Reading…

More Options for Activity Mapper

Activity DisplayHere’s another way to analyze trip history data from Capital Bikeshare. Back in March, I had used Processing to create QuickTime animations that I uploaded to YouTube (see Neighborhood CaBi Animations). But I wanted a tool that let the user control the flow of time, as well as how to customize the display. A few weeks ago, I created a tool to do this for Metro (see A Day of Metro, Entries and Exits). Now you can use the same tool to show CaBi data: go to the Activity Display home page to select which data set to use, or add ?system=cabi to the URL to go straight to the CaBi display.

I show data in 5-minute increments for Saturday, September 14, 2013. That day was the busiest day in the 3rd quarter, with 84,8755 trips made in a single day, using the system’s 243 stations. (Today the system has 300 stations.)

This is now the third tool in my collection of data visualization programs. The Stat Mapper shows collections of single points; the Trip Visualizer is meant for displaying point-to-point data; and now the Activity Mapper is for chronological data. Over time I hope to add new data sets as well as new features.

Animating a Day of CaBi Data

Want to see how people move in and out of Metro stations? I made a Metro Activity animation using data from April 10, 2013. The data shows the numbers of entries and exits for each station in 15-minutes increments, from 4:45am to 1:00am (that’s 81 records).

WMATA has already visualized this same data set, in Visualization of Metrorail Station Activity. The date was picked because it had the 4th-highest ridership, with 871,000 trips, compared to 750,000 on an average weekday.

My goal for this new visualization was to design a tool that’s fluid and interactive. I used the HTML canvas element to create the animation. I can scale the canvas to fit the window. On top of each station, I draw an image that’s scaled to the data for that station. I can change the color and shape to indicate other values. A form on top shows the user controls. » Continue Reading…

Protesters came to Washington, DC to show support for reigning in the abuses by the National Security Agency. On October 26, the Stop Watching Us rally against mass surveillance was held outside the Capitol. A coalition of groups called the NSA surveillance apparatus “a stunning abuse of our basic rights.” Speakers included security expert Bruce Schneier and Congressman Justin Amash. Photos below.

The Stop Watching Us rally
NSA: Hands Off Our Data
» Continue Reading…

Protesting Government Spying Abuses

Mondays in October are home to a serialized theatre event that I’ve been lucky enough to attend for the past two years. Like soap operas, the Hope Operas feature recurring characters and advancing plots. Though self-contained, the real fun is to return to see cliff-hangers resolved and characters grow. For 2013, their fifth year, the theme was “cartoons for adults.” Here are photos and summaries from the five shows that contributed episodes.

2013 Hope Operas
John Tweel, Tony Greenberg, Catherine Aselford, Andrew Lloyd Baughman, and Jefferson Farber
» Continue Reading…