Strava Heatmaps on the Cheap

Strava has been wildly successful at getting people to surrender their privacy in the name of bragging about fitness. You log your activity on the Strava website, and from this you can make personalized maps. You can even share this information up into a global heatmap database, from which Strava can show you where EVERYBODY has been running and biking and snowshoeing and paragliding and dolphin-riding and so on.

It’s a lot of fun to play around with. Shown below, we’re zoomed in on Cambridge and Boston. It’s no surprise that busy streets are busy, but I like how you can see exactly where the gaps are under the Harvard Bridge. The Charles River looks like a highway. Which, for the purposes of sport (and fish), it is.

I was jealous of these personal activity maps, but not jealous enough to spend the money on Strava. That was when I remembered something important, something that I try to remind myself on a regular basis: whenever you imagine a potential app or web service, you cause somebody to retroactively make it for you. That is to say, your idea isn’t original, so someone has already done it for you. All you have to do is say “All-seeing Google, show me the thing that does X.”

As in the sentence: “Show me the site that will let me make my own Strava-like heatmaps for free.”

I know this is kind of obvious, but sometimes I forget to actually make a pointed request for something that is vaguely floating around in my mind. I’m kind of thinking about it (“gee, that Strava heatmap is cool…”), but I don’t articulate the specific question. This means that the app never gets retroactively created by internet elves on my behalf. You see how it works? The magic never happens.

Anyway, I was not disappointed. I was led very quickly t0 dérive by Erik Price. It’s free! It’s open source (MIT license)! It’s very good, and it works like a charm. Huzzah! How I love the new millennium. And thank you, Erik.

You just bring your own GPX files to the dérive website, and then drag them onto the browser. All the work happens in the browser, so you’re not actually sending any of the files back up to the site.

This pandemic has given me a lot of time to walk around my hometown, and my completionist tendencies coupled with a nice route-planning app (Footpath) have given me the motivation to explore.

How it started: