Many years ago I wrote a tutorial on how to use an ArcGIS plugin to convert a transit agency’s GTFS package – a group of files that describe when and where their buses and trains stop – into files that could easily be manipulated by popular GIS desktop software.
That was so long ago, before I became an expert in using QGIS, a free and open source alternative to ArcGIS.
This tutorial will show you how to convert GTFS to a shapefile and to GeoJSON so you can edit and visualize the transit data in QGIS.
First you’ll need to have QGIS installed on your computer (it works with Linux, Mac, and Windows). Second you’ll need a GTFS package for the transit agency of your choice (here’s the one for Pace Suburban Bus*, which operates all suburban transit buses in Chicagoland). You can find another transit agency around the world on the GTFS Data Exchange website.
Section 1: Let’s start
- Open QGIS.
- Load your GTFS data into the QGIS table of contents (also called the Layers Panel). Click Layer>Add Layer>Add Delimited Text Layer. You will be adding one or two files depending on which ones are provided.
- Now, here it can get tricky. Not all transit agencies provide a “shapes.txt” file. The shapes.txt file draws out the routes of buses and trains. If it’s not provided, that’s fine, but if you turn them into routes based on the stops.txt data, then you will have funny looking and impossible routes.
- Click on “Browse…” and find the “stops.txt”. QGIS will read the file very quickly and determine which fields hold the latitude and longitude coordinates. If its determination is wrong, you can choose a different “X field” (longitude) and “Y field” (latitude).
- Click “OK”. A new dialog box will appear asking you to choose a coordinate reference system (EPSG). Choose or filter for “WGS 84, EPSG:4326”. Then click “OK”.
- The Pace bus stops in the Chicagoland region are now drawn in QGIS!
- If the GTFS package you downloaded includes a “shapes.txt” file (that represents the physical routes and paths that the buses or trains take), import that file also by repeating steps 4 and 5.
Section 2: Converting the stops
It’s really easy now to convert the bus or train stops into a shapefile or GeoJSON representing all of those points.
- Right-click the layer “stops” in the table of contents (Layers Panel) and click “Save As…”.
- In the “Save vector layer as…” dialog box, choose the format you want, either “ESRI Shapefile” or “GeoJSON”. **
- Then click “Browse” to tell QGIS where in your computer’s file browser you want to save the file. Leave the “CRS” as-is (EPSG:4326).
- Then click “OK” and QGIS will quickly report that the file has been converted and saved where you specified in step 3.
Section 3: Converting the bus or train routes
The “shapes.txt” file is a collection of points that when grouped by their route number, show the physical routes and paths that buses and trains take. You’ll need a plugin to make the lines from this data.
- Install the plugin “Points to Paths”. Click on Plugins>Manage and Install Plugins… Then click “All” and search for “points”. Click the “Points to Paths” plugin and then click the “Install plugin” button. Then click “Close”.
- Pace bus doesn’t provide the “shapes.txt” file so we’ll need to find a new GTFS package. Download the GTFS package provided by the Chicago Transit Authority, which has bus and rail service in Chicago and the surrounding municipalities.
- Load the CTA’s “shapes.txt” file into the table of contents (Layers Panel) by following steps 4 and 5 in the first section of this tutorial. Note that this data includes both the bus routes and the train routes.
- Now let’s start the conversion process. Click on Plugins>Points to Paths. In the next dialog box choose the “shapes” layer as your “Input point layer”.
- Select “shape_id” as the field with which you want to “Point group field”. This tells the plugin how to distinguish one bus route from the next.
- Select “shape_pt_sequence” as the field with which you want to “Point order field”. This tells the plugin in what order the points should be connected to form the route’s line.
- Click “Browse” to give the converted output shapefile a name and a location with your computer’s file browser.
- Make sure all of the options look like the one in this screenshot and then click “OK”. QGIS and the plugin will start working to piece together the points into lines and create a new shapefile from this work.
- You’ll know it’s finished when the hourglass or “waiting” cursor returns to a pointer, and when you see a question asking if you would like the resulting shapefile added to your table of contents (Layers Panel). Go ahead and choose “Yes”.
- Now follow steps 1-4 from Section 3 to convert the routes/lines data to a shapefile or GeoJSON file.**
* As of this writing, the schedules in Pace’s GTFS package are accurate as of January 18, 2016. It appears their download link always points to the latest version. Transit schedules typically change several times each year. Pace says, “Only one package is posted at any given time, typically representing Pace service from now until a couple of months in the future. Use the Calendar table to see on which days and dates service in the Trips table are effective.”
** Choose GeoJSON if you want to show this data on a web map (like in Leaflet or the Google Maps API), or if you want to share the data on GitHub.