OpenStreetMap

Routesheds

Posted by Minh Nguyen on 13 October 2014 in English (English)

Warning: This post makes absolutely no sense to anyone outside the United States, or to anyone who relies on a mode of transportation that uses a sane numbering scheme.

Development on the OSM U.S. shield renderer seems to have stalled a bit, and my request to render pictoral route shields on the Standard stylesheet is effectively tabled for now. There doesn’t seem to be a whole lot to get excited about on the shield rendering front.

Just to bide my time, I decided to approach route shields from the other direction, using OpenStreetMap’s coverage of the Cincinnati Tri-State area as a starting point. Slapping shields in random locations all over a road map is so… functional. So let’s ditch the map, fire up TileMill, and let the shields do the talking:

The first thing you see

A bit of a mess, isn’t it? It’s even worse when you zoom out:

The next thing you see

But pan around, and you might start to notice some patterns if you’re from the area. You can make out the most prominent highways. Here’s a map Nate made from OSM data, for comparison:

Back to reality

You can make out the Ohio–Kentucky state line where the state route shields in the shape of Ohio turn into plain old circles:

These states have a lot in common, really

So what’s going on? Each shield on the grid indicates the nearest Interstate, U.S. route, or state route, with an understandable bias towards highways over surface streets. A shield isn’t necessarily positioned along the route it indicates; rather, it just happens that no other route is closer. That property gives rise to an interesting phenomenon that I’ll take the liberty of calling a routeshed. Much like a watershed, a routeshed encompasses the area in which cars naturally flow toward a single route. OK, that sounds so ridiculous it belongs in a Wikipedia article. But this is what the sparse terrain of western Hamilton County looks like:

No choice but the Interstate

If you’re as sleep-deprived as I am, it does kinda-sorta look like a watershed.

Here’s the full slippy map.

Credits: Road data from OpenStreetMap contributors, mostly me, Nate, and NE2. Shield blanks from Wikimedia Commons users SPUI, Ltljltlj, Fredddie, and Scott5114. Shield labels set in Roadgeek 2005 Series C and D. Code under the MIT license; tiles under Creative Commons Attribution 4.0.

Location: Betts-Longworth Historic District, West End, Cincinnati, Hamilton County, Ohio, 45203, USA

Comment from HannesHH on 14 October 2014 at 21:25

Ahaha, that’s awesome :D

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