MapRoulette is overdue for a new challenge, and we have one that should keep us busy for a while: adding numbers of lanes to the main roads in N-America. This information would be great to have for advanced visualization and transportation analysis purposes. And a lot of it is already there, so let’s just make it complete.
The challenge works as follows: You fire up MapRoulette as usual by going to maproulette.org. You are presented with one OSM way somewhere in North America that does not have a lanes=* tag. (We only care about secondary and higher to keep things useful and manageable, and we’re starting with the motorways and moving down, so you should see only motorways at first.)
If you want to fix this road, click on ‘Edit in JOSM’ and wait for the way to load in JOSM. Make sure you have JOSM running, otherwise the button won’t work.
To actually see the number of lanes of this road, you may need to zoom in a little.
Aha! This road has two lanes. So we go ahead and add that as a tag to the road. Hit Alt-A (Option-A on a Mac) or click ‘Add’ in the Properties pane:
And enter the information in the tag dialog:
Now upload your change, adding a brief changeset comment in which you should mention you used MapRoulette – for example by adding #maproulette:
Then, return to MapRoulette and indicate that you have fixed the problem!
Not all cases are this simple. There’s a few things you need to look out for.
In some cases where the amount of data to load into JOSM would become too big, JOSM will only load the actual way that requires your attention, not the data for the entire area.
Here’s an example:
If you zoom in and deselect the road, you can see that this road is marked as oneway.
Because this looks like a dual carriageway road from the aerial imagery, there is probably another OSM way representing the other side of this road. If unsure, confirm by loading more data.
In these cases where only the actual way is loaded, you should also avoid moving or deleting nodes from the way, as these nodes may be shared with other ways you cannot see. Before you make any such changes, load more data.
Also, only enter the number of travel lanes and do not include merge lanes. Here’s an example:
The right lane is a merge lane, and does not count towards the main road lane count. So in this case the way would get lanes=3. You can see that it’s a merge lane by looking at the context (pan around and you will see the ramp) as well as by the difference in lane markings.