Awesome idea and data set, however I'm very skeptical about its quality. Random analysis: the city where I live in Brazil (Curitiba/PR) shows major avenues and bus lanes as heavily used by bikes and for running, which is partly true but it's far from as heavy as the map makes it seem; my hometown 500km from here (Praia Grande/SP) has 7x more exclusive bike lanes and running trails and yet its usage is just average while everybody I know there rides a bike (not to say the most used bike/run path the maps shows there is actually a interstate freeway).
My family almost got killed once because of a bad judgement based on computer maps.
My wife and I were on a cross-country bike trip, with our dogs in tow. On this particular day, we were shooting for the Chicago area and had a long way to go from Ransom, Illinois where we woke up. There was nothing but corn, windmills, and an Air Force special training center. But we had a friend in Oak Park, and we were determined to get there and take a rest day.
After following a number of scattered trails and highways, we wound up lost in a kind of industrial alcove, trying to cross one of the canals. After a little backtracking (which is the worst), we stopped to ask for help from a bald guy in a pink tee shirt whom I'd noticed cycling earlier. He was a German guy named Rolf and he apparently biked about 60 miles a day just for fun. He told us we still had pretty far to go, and he rode with us about ten miles or so to his car, where he had a map book. He gave us detailed directions saying exactly what would be the best and safest route. We thanked him and went our separate ways.
We followed his directions until after dark (at which point we would normally have stopped). We'd already traveled close to ninety miles that day, and were getting anxious to get off the road. At some point, we called our friend to see if we were close. We told her Rolf's directions and asked if that would get us there. She said she would look online.
She called us back with a different set of directions, and, figuring that she should know her own neighborhood, proceeded to follow them. This took us onto a road that, we later learned, wound through what is essentially a wildlife refuge, and which quickly became extremely dangerous. There were no street lights, and cars were coming around turns at high speed. We decided to stop and barely got off the road in time to avoid being hit. We then had to get our bikes, dogs, and trailer across the street so we could walk the path. It was one of the scariest experiences of my life.
I later found out that our friend had never been on the road she recommended, and was going only by what it "looked like" on Google maps. (This was 2008, by the way.)
So yeah, quality. And there's no substitute for human expertise.
EDIT: and yes, it was our bad judgement as well, for taking bad advice... and maybe for not having our own maps in the first place. Although I've done thousands of miles of cross-country (in the US), and I think you really do have to wing it.
Haven't done much bicycle touring, but I've had motorcycle wheels in all of the lower 48 and parts of Canada. Something I learned years ago is to never ask locals for directions. First, a lot of people know how to get to work and to the grocery store, and that's it. Oh, they'll pretend to offer directions because no one wants to look like an idiot who doesn't know their own town. Second, even if the local knows the way their directions will be filled with all kinds of assumptions that are valid for someone who lives in the area but not for someone who is seeing the area for the first time.
Now, convincing my wife of this truism has been something I've worked on for twenty years of marriage ("why don't you stop and ask someone?" "Because it likely won't do us any good."). Thankfully GPS navigation units have made the debate somewhat moot. :-)
One big difference with this data set is that it's pulled from tracks traced by Strava users. So, modulo malicious uploaded tracks, these are all tracks that have been ridden, by definition. And if a given route is "hotter", that means more people have ridden it.
I'd fight with all my soul to prove that's utterly wrong, at least regarding the issues I've mentioned above. If the data is not 100% open it's impossible for it to be so reliable. And even if it is, that doesn't mean it's good data at all.
I think you are being a bit cranky about it, the text on the control panel says exactly what it is. The mechanics of the colorization aren't very apparent though.
It would be interesting to see different splits of the data, I imagine Brazil routes normalized nationally would do better with your example.
