Visualizing Rail Flows in Canada

by Willem Klumpenhouwer

Thursday, January 03, 2019

In 2016, 284,548,423 tonnes of goods were moved by rail to, from, or within Canada. That's over half the weight of all humans on earth.

Statistics Canada regularly collects and publishes information on the tonnage of goods that move in and between provinces and regions in North America. Because this data involves flows between and within regions, it is a good candidate for visualization with a chord diagram.

Below, you can view flows between regions as represented by "chords" moving between the edges of a circle. The width of the chord as it meets the edge of the circle represents the proportion of goods that moved from that region to the other end of the chord. The colour of the chord corresponds with the region that has the highest net flow of the two ends.

Hover over an individual chord to see the flows between those regions, or hover over a portion of the circle to isolate those flows from the rest of the diagram. Use the dropdown to select individual commodity groupings as provided by Statistics Canada, or choose "all commodities" to see the total amount of traffic.

Railway goods movement in Canada and North America

From this single diagram, we can gain a lot of insight about how goods are moving in the country by rail. Here are a few examples:

  • From the "all commodities" data, we can see that most provinces are net exporters of goods by rail when it comes to weight. This reflects huge natural resources production, and the fact that natural resources are good candidates for rail travel. Selecting goods such as "potash", "fuel oils and crude petroleum", and "lumber" tell a story of what different provinces produce.
  • Select "prepared foodstuffs" from the list of commodities. Here we can see that Ontario is a net importer of prepared foodstuffs from the US & Mexico, but a net exporter of these goods to other provinces in Canada.
  • By selecting "coal" as our commodity, we can see that British Columbia produces the vast majority of coal, and that most of it stays in the province as it's transported by rail. This reflects coal being moved to tidewater at ports in the province. A large amount of coal produced in the US/Mexico also moves into BC.

This is the power of good visualizations. They allow us to think about our data in multiple ways at once, and interactivity allows for exploration of the data and spurs further questions which we can dig into further. The chord diagram shows proportionality, movement, and comparitive relationships all at the same time. It's one of my favourite diagrams.