[talk-au] Roundabouts and routing

[Steve Bennett]

On Sat, Dec 19, 2009 at 8:31 AM, Roy Wallace <waldo000000 at gmail.com> wrote:

> The real issue here is "what are we mapping" - and with the
> intersection example, the issue seems to be whether the ways should
> accurately correspond to geographic reality  (_messy), or not
> (_simple).
>

IMHO, it's quite simple: we probably want both, and we want to distinguish
between them.

Presumably in the history of the project, at first it was enough to simply
say that two major intersections met. Then we began to mark slipways and
split the two sides of the road. Then we're marking pedestrian crossings,
traffict lights, turn restrictions, traffic islands etc. And we're trying to
make all this work for routers, renderers and other tools, without giving
them any hints.

I don't think this can work. You need to give those tools some hints. In the
simply/messy case, it seems to me that the extra curves are not "geographic
reality" so much as they're "routing reality" or something. They just
correspond to paint and signs, right? Would you ever render them? Well, a
little extra tag distinguishing them from the main road, which definitely
needs to be rendered, would be appropriate.

<prepares for deluge of "no tagging for the renderer/router">

Steve
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