Data Visualization

Making Sense Of Data

The next time your bus is late, remember there are hundreds of other buses out there trying to get thousands of other people where they need to go.
What Does 6,500 Bus Trips Look Like?

Visualizing Pittsburgh Transit

Port Authority makes over 6,500 trips every weekday, racking up 213,000 rides. That’s like moving nearly 20% of the entire county’s population every day. How can you fathom 6,500 trips per day? What does that look like? We wanted to find out.

First, the data.

Many transit systems publish their schedule data in the General Transit Feed Specification (GTFS) format. These files describe all the system’s routes, stop locations, trips, and stop times. Mapping services like Google use these data to provide transit directions.

First, consider the routes. Port Authority has over 300. GTFS data includes a shapes table of the latitude and longitude point sequence for each route. To plot these, we used PostGIS to convert them into lines and exported them to GeoJSON. Using Leaflet and D3.js, Steve mapped them.

Data Wrangling

Mapping routes is only step one. There were numerous challenges to follow which are detailed in the full article about this project. The final product is pretty cool. Remember, all of this comes from data stored in numerous databases. Visualizing it is complicated to build, but simple to digest.