heatmapThe Trip Visualizer now lets you review the data using heat maps. I had introduced heat maps in the Stat Mapper (which maps points) and wanted to try the same thing for the Trip Visualizer (which maps vectors).

Because many of the visualizations are for bike data, for which I use Google Map’s green bike layer, I wanted to change the default red-yellow-green gradient of the heat map. Instead, I have a “blue flame” gradient (red-indigo-blue), hoping for a higher contrast.

One of the advantages of the heat map is it simplifies all the various data points into a smooth field. The Bixi Montreal Trip Visualizer shows 410 stations, and when each point has an arrow coming out of it, the resulting diagram can be too busy and too dense.

calhounThe heat map now makes it clear if a station has a lot of “loop trips.” Since I can’t draw an arrow pointing to the same spot where it begins, the old method couldn’t display loop trips (though they are included in the info-window when you hover over a station).

In this image from the Nice Ride Trip Visualizer, I’ve selected Lake Calhoun Center, a station where 58% of all trips are loop trips. You can see how the arrow makes it look like the most popular destination is the station at Lake Street & Humboldt, a bit to the east. But the heat map makes it clear that most riders from Lake Calhoun Center in fact end up back at Lake Calhoun Center.

It’s interesting to try the heat map with clusters. You can find pre-programmed clusters (if any) at the bottom of the drop down, or create your own: the “1” key selects all stations in view, and “2” lets you move a circle around to select station.

gtownLooking at Georgetown’s four CaBi stations in Washington, DC, we’ve already seen how it appears most riders use CaBi to travel in or out of the neighborhood, not within it. (See Neighborhood Clusters Added to Updated Capital Bikeshare Trip Visualizer.) The heat map makes this conclusion a bit more dramatically than all those lines running everywhere.

You can turn on the heat maps using the check-box in the upper-left-hand corner.

Read more about the Trip Visualizer: A Day of Bikesharing in Montreal, Metro Trips Visualized, and Seven Months of Nice Rides.

Cooking Data with Heat Maps

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