New MapRoulette Challenge: Crossing Ways

Posted by mvexel on 30 June 2014 in English. Last updated on 1 July 2014.

We created a new MapRoulette challenge over at Telenav: Crossing Ways. As always with the Telenav-generated challenges, this one is US only, because we currently only process OpenStreetMap data for the United States. We are working on extending support for other regions.

TL;DR –> On to MapRoulette!!

The Crossing Ways challenge is pretty straightforward and should make for an easy challenge for novice mappers looking for something to fix. It detects ways that cross, but neither way is tagged as a bridge or tunnel. Here is an example:

Example from MapRoulette

If you open this up in iD or JOSM, you will be able to tell the required resolution from the aerial imagery:


In this case, the ways should be connected as there is clearly an intersection. Another possibility is that there actually should be a bridge or tunnel tag on either of the ways.

In this particular case, you can see that there actually is a node at the intersection, but it does not connect both ways. In JOSM, it displays as a ‘skinny node’:

Skinny node in JOSM.

In this case, you can use JOSM’s ‘Join’ function (shortcut ‘J’) to connect both ways. In iD, a node connecting two ways will be grey, and a regular node will be white:

Nodes in iD

If you use iD, you can just drag an existing node to the intersection to snap the two ways together, or drag a virtual node to the intersection to create a new intersection node. (Virtual nodes appear between two existing nodes and allow you to quickly create a new node on a way, an example shown below.)

virtual node in iD

There are currently around 19,000 cases in the US alone, so let’s get on fixing these annoying bugs in OSM!

On to MapRoulette!


Comment from todrobbins on 30 June 2014 at 17:01

Great work mvexel!

Comment from jumbanho on 30 June 2014 at 17:27

Does this work for cycle/foot- ways, paths and tracks, too?

Comment from mvexel on 30 June 2014 at 18:18

jumbanho - those are excluded for now, but it’s a good idea for a followup challenge.

Comment from Alan on 1 July 2014 at 01:01

I think the URL in your last link “On to MapRoulette” is broken. Needs the http:, I think.

Comment from mvexel on 1 July 2014 at 03:08

Thanks @Alan, fixing…

Comment from AndiG88 on 1 July 2014 at 06:08

I think also displays those, if you want to fix them outside the US.

Comment from Pieren on 1 July 2014 at 13:11

I’m assigned to this “challenge”:

What is wrong here ? is it possible that “bridge=viaduct” is not recognized by the QA tool ?

Comment from mvexel on 1 July 2014 at 14:51

Pieren: You have discovered a bug. bridge=viaduct was not processed and will appear as false positives. We are working on a fix! This is less than 1% of bridges in the US, most are just bridge=yes. We discovered another bug where we did not recognize _link ways that are also tagged as bridge (or tunnel). This is also being fixed.

Thanks for reporting!

Comment from mvexel on 1 July 2014 at 14:53

AndiG88 - correct. I still want to get closer collaboration with KeepRight, and have been in touch with the author before, but due to a lack of time on my part, I haven’t been able to follow up.

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