On Fri, Feb 5, 2010 at 7:13 AM, Roy Wallace <waldo000...@gmail.com> wrote: > On Thu, Feb 4, 2010 at 8:06 PM, John Smith <deltafoxtrot...@gmail.com> wrote: >> >> Imagine a mechanism in your favourite editor when you can drag the >> "width" of the node outwards to match the width of the road, this then >> gets stored against the node information for the way. > > Ah ok. Hmm, I'd prefer that the OSM way is the centerline of the > feature. This would mean: > 1) the OSM way is consistently meaningful in itself, and matches current usage > 2) you only have one width value per node, which might simplify editing.
I think I'm inclined to agree. Any renderer that supports all these tags won't be particularly inconvenienced by the fact that the line isn't down the centreline, and any renderer that doesn't will do a better job of rendering it. That said, it would be fairly rare for the central divider to be far from the geometric centre of the road for a non-divided highway, wouldn't it? Are there really that many asymmetric roads, with say one lane on one direction, and two in the others (as in the diagram)? The biggest problem I see with John's proposal (as I understand it) is that it adds lane information not onto nodes, and not onto ways, but onto the *relationship* between ways and nodes. I could be misunderstanding it, as I'm not really familiar with the underlying data structure. And in any case, lane information is intuitively not a property of a node, but of a section between two nodes. This proposal would appear to make it very easy to make long sections of road where the number of lanes is changing - not particularly useful. In fact, I'm not sure it's even useful to be able to code that. > But it seems like you're suggesting that the OSM way instead should represent: > a) if a oneway feature: the centerline > b) if a twoway feature: the divider between traffic travelling in each > direction It does seem a bit inconsistent. A three lane one-way road will have the way running down the centre of the middle lane. A three lane two-way road will have it running between two lanes. Or, to put it differently, for a given way with lane tags, where a renderer should render the road will depend on the property of the oneway=* tag. Which is extremely counterintuitive. Steve _______________________________________________ Tagging mailing list Tagging@openstreetmap.org http://lists.openstreetmap.org/listinfo/tagging