[OSM-newbies] divided but not seperated

[Matt Williams]

2009/8/24 Robert Helvie <alimamo at gmail.com>:
> Hi,
> The city I am mapping has recently started to divide certain of the larger,
> more major, roads that I originally mapped as single ways. Now, all they are
> really doing is putting a concrete strip down the center with shrubs, or
> even in some cases, just installing metal "bollards" down the centerline. I
> assume this is to prevent people from driving across on cross streets or to
> stop people from making crazy u-turns.
> In any case, I have to assume each side should be mapped as a one-way road
> now. My question is ... In the editors, is there an easy way to draw the
> roads so they appear next to each other without overlapping in the render?

Well, a lot depends on what zoom level you view it on. Any motorway
will overlap between the lanes at z13 but at z18 they will usually be
visually separable.

> (Is this important?) Is there a distance between the ways (centerline) that
> would provide a good approximation. Note that the roads often don't have
> lane or width tags yet. Do the renders or editors take those tags into
> consideration?

You should draw the two lanes as far apart as they are in real life.
For the sort of roads you're talking about they will almost certainly
be drawn overlapping at most zoom levels but that really doesn't
matter. This is a good example of a time when you shouldn't map for
the renderer.

> I generally use JOSM. Is Merkaartor better for visualizing the "final"
> product? Has anyone had any hands-on with CloudMade's Mapzen? Alas, I am in
> Asia.

Perhaps Merkartor is better at looking like Mapnik but that doesn't
mean that the data is any better. Remember, you've also go to be
mapping such that the data can be used for routing and cycle maps and
orienteering maps and so on.

Regards,
Matt Williams
http://milliams.com