November 30th, 2013 | no comments
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…
November 25th, 2013 | no comments
New 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…
November 21st, 2013 | no comments
Here’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.
November 11th, 2013 | 4 comments
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…
August 3rd, 2013 | 1 comment
The Citi Bike Mapper application shows all of the new bikesharing stations in New York City. Like the official Citi Bike station map, my version plots markers across a map of the city. But to make it easier to gauge how full or empty a station is, I write the totals across each marker.
Whether you care more about avoiding empty stations or full stations depends on whether you’re planning to check in or out. So, to de-clutter the screen, you can select to show only the number of bikes or docks at each station. You can also show this as a percentage of total slots. Use the “wordy” check box to shorten the markers to just numbers. Or, another option lets you display just the name of each station.
The color or each bubble will always indicate how full or empty the station is, ranging from blue for empty to red for full. Shades of purple are used for proportions in-between. » Continue Reading…
July 16th, 2013 | no comments
Inspired by the Apple TV screen saver, I created a way to display photos from Flickr on a web page. The display has three planes of photos to create a three-dimensional illusion, with fast-moving large images in front and slow-moving small images in back.
The Scrolling Display program is at mvjantzen.com/flickr/display.html. You can choose photos by selecting a user, a tag, or a set. You can also combine a user with a tag. After clicking “display photos”, you’ll see your options in the URL, and in fact you can edit the URL directly to modify your options, or use the link to share, such as mvjantzen.com/flickr/display.html?tags=transpocamp2013. » Continue Reading…
July 9th, 2013 | no comments
Here’s a new game your kids might enjoy. Letterball tests your skill at re-arranging letters in the right order to spell a word. The words are the names of commonly-known animals (there are 32 different animals). Click on the balls to spell the word left-to-right. You can undo a guess by clicking on it again.
June 30th, 2013 | no comments
Discover local bike shops with Bike Shop Mapper. This web page puts nearby bike shops on a full-page map. There are three ways to pick a location: by allowing the program to get your mobile device’s current location, by entering the name of a place (or ZIP code) into the “Places Autocomplete” input, or by panning the map and pressing “find bike shops.”
The data comes from Google’s list of places with “bicycle store” entered as a category. They have bike shops all over the world, but only if the shop has a page on Google+.
The bike icons will be light green if the shop is currently open, dark green if closed, and medium green if unknown. » Continue Reading…
June 28th, 2013 | 1 comment
Do you wish you could discover local farmers markets as you visited new places? Here’s a web app that makes it easy: the Market Mapper application. It uses data from the U.S. Department of Agriculture of all farmers markets in the U.S.A.
The program uses your current location to display the closest farmers markets. You can also type a place in the “location” field. As you pan the map, hit “find markets” to look for more locations. » Continue Reading…
June 21st, 2013 | no comments
I had seen beautiful, interactive bar charts written in D3, and wanted to create my own. At d3js.org you’ll find many great examples.
Site by M.V. Jantzen