[OSM-talk] Ways, boulevards, divided highways

Andy Robinson Andy_J_Robinson at blueyonder.co.uk
Thu Mar 23 09:25:14 GMT 2006


Alex Mauer wrote:
>Sent: 22 March 2006 22:56
>To: talk at openstreetmap.org
>Subject: [OSM-talk] Ways, boulevards, divided highways
>
>With the new support for ways, some questions have come up in my mind
>
>Are ways supposed to represent entire roads, or just sections of roads?
> If they're supposed to represent entire roads, what about instances
>where multiple road names share the same physical piece of road?

That's up to you. There is no need to make a very long route into a single
way, in fact I would advise you not to do this, especially as at the moment
there is no possibility for insertion of a new node into an existing way (or
segment). What I am doing is creating ways for logical similarity. So if all
the features of a particular set of segments are common (eg name, highway
class etc) and I am confident that no new nodes along the way are required
in the near future, then I tag this section as a single way. For residential
streets this means usually the whole street. For major roads however I am
finding it more practicable to limit the way length to major intersection to
major intersection.

Ways can overlap each other, although as yet the methods of selecting
individual overlapping way layers is not ideal. That will flush out with
time and use.

>
>On a different note, what's the "correct" way to handle boulevards,
>divided highways, 4-lane roads, and transitions among them? Should they
>be 2 lines each or one?  My thought is, 1 line for each of the above
>except divided highways, which should get 1 line per direction.

The general consensus is that you draw a line for each separate physical
feature. So, if your highway is physically divided you draw two separate
lines.
For a boulevard where you can drive across between each tree, then that's
probably closer to a single line rather than two lines with lots of cross
connections, but I would say that it's a users preference when editing as to
how they draw it. You can always tag the highway as being a boulevard so
that its possible to render it differently than for a normal highway on
output versions.

One thing to bear in mind is that if the data is used for navigation then
it's a lot cleared to the navigation algorithms if the layout in the data
matches the layout on the ground.

>
>Is this the consensus on the list?
>
>-Alex Mauer "hawke"


cheers,

Andy





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