Strava, an online anxiety creation and distribution network built specifically for wannabe bike racers and joggers, has created something genuinely useful with all the data they've been snagging off our phones and GPS devices.

Behold! The Strava Global Heat Map. The visual representation of where people ride and walk the most, laid over Google's global surveillance – I mean, global land survey.



This is a powerful tool, indeed. People with a vested interest in the design and implementation of land usage policies (urban designers, mayors' office staff, activists) can use this map to find out where people go, versus where the street design wants them to go.

Or, more accurately, it shows where bikers with smart phones who like to street-race imaginary competitors on their commute go. But still, that's something.

What I find most useful about this technology is that you can use it to hunt secret mountain bike trails and race courses.

To do this, simply zoom in and out on the map and look for sudden flashes of white in areas where there are no roads. Here are a few I found.

The Dan Ryan Woods Cyclocross Track:

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The U of W Parkside Offroad Trails:

I've ridden here once before. The trails are shared-use with hikers, but they're pretty fun. Also, they're unmarked and unofficial, so obviously there's no trail head. This map is useful for finding how to get on the right trail.

Silver Lake County Park Trails:

These trails are sanctioned, but they just aren't very well known, except to a dedicated handful.

Though, it's important to note that Strava selects for a certain type of person: somebody who is willing and able to download their app. Thus, the Global Heat Map has some fairly large blind spots, which we can see from this shot of Lane Tech High School:

The above heat map is important because this little acreage is one of the most heavily trafficked pieces of land in the City of Chicago. Not only is there the constant patter of high schooler feet, but The Garden bike park is located in the dead center of this shot. The Garden is among the oldest and most renown bike parks in the world (amongst a certain demographic). It's existed in one form or another for over thirty years, and sees use all day, every day (unless the jumps are wet). According to Strava, it hardly exists.

And that's an important lesson for people who use this type of technology. Strava is a tool, not a god. It self-selects for middle-class, athletic urbanites in the upper-median age range, and displays a map of where they like to ride for recreation.

What worries me about Strava Metro, the urban planning consultancy arm of Strava, is that its data promotes the allocation of resources to the types of people who use Strava. On a map of Chicago, Strava's heat map seems to have an inverse relationship with a crime heat map, despite the fact I can attest (with very strong anecdotal evidence) that walking and bike usage are just as important in the high crime areas as they are in the other parts of the city.

This is a heat map of violent crime in Chicago

Strava doesn't seem to have much data on the high-crime areas, despite the fact that people probably walk and ride bikes in these areas just as heavily as the rest of the city.

So what I'm getting at is Strava can be very useful for finding out where Strava users like to ride (especially the secret spots) but that's about the end of its value.

I'll leave you with one last little tip for finding secret trails: look for squiggly lines on the municipal grid. Here's one from Iowa City:

The bright trail is sanctioned, the darker ones are not–but they're also a lot more fun. Keep an eye out for the little trails that shoot off the main trail, those are the bread crumbs to Funville.