[OSM-talk] correctly mapping avenues

[Karl Newman]

On Feb 11, 2008 7:20 AM, Bernd Raichle <bernd at dante.de> wrote:

> Hi,
>
>
> on Sunday, 10 February 2008 08:34:31 -0800,
> Karl Newman <siliconfiend at gmail.com> writes:
>  > On Feb 10, 2008 4:21 AM, Frederik Ramm <frederik at remote.org> wrote:
>  > > > Since trees lining a way/street are such a common occurence, why
>  > > > not have a simple additional tag to the main road.
>  > > >
>  > > > lined_by_trees=yes/no/left/right
>  > >
>  > > I'm a bit unhappy about needlessly inflating the importance of the
>  > > direction of ways. Long-term, I would actually like to get rid of the
>  > > direction and express everything in relations.
>
> This means, that you find it necessary to have something like a
> "direction" or a "side", both of this features related to a way?
> But you don't want to express a direction or a side by the _implicit
> order_ of the way nodes.
>
>
>  > >                                                 The reasons for this
>  > > are
>  > >
>  > > (a) the direction is too easily changed, sometimes by mistake
>
> ... because none of the current OSM editors show direction- or
> side-related tags explicitly.
>
>
>  > > (b) there might be multiple conflicting things that rely on the
>  > >    direction, e.g. a road that is oneway from A to B but has a
>  > >    slope from B to A
>  > >
>  > > Anything with "left/right" in it also relies on direction. I'd prefer
>  > > "east/west/north/south", or using an explicit relation that says
>  > > "trees on the right between nodes A and B along road C".
>
> I am against east/west/north/south because there are a lot of
> ways/areas/things which do not go straight ahead.
>
>
>  > Okay, this thread is at risk of spinning wildly off-topic, but I've
> been
>  > thinking about this situation recently. It seems to clamor for the use
> of
>  > specialized relations that are "direction-aware". That way, if a way is
> a
>  > member of a relation and has directional properties (left/right), then
> the
>  > editors could look for those relations when the way is reversed and
> either
>  > fix them automatically or at the minimum raise a warning dialog.
>  >
>  > I also had some other ideas about enforcing referential integrity for
>  > another type of specialized relation (if one or more node relation
> members
>  > is required to be part of a way relation member, then enforce that
> rule).
>  > That rule could actually be enforced by the API.
>  >
>  > These specialized relations would just give some structure to the
> wide-open
>  > relation type, without implying anything about the nature of the
> relation.
>  > It could possibly be accomplished through special tags on the existing
>  > relation structure.
>
> Do you have any propositions how this will look like or how this
> should be done?
>
> A few days ago I have started a new proposal for a "Segmented Tag",
> which relates a set of tags to a directed or undirected part of a way
> (I have called this part "segment" inspired by GDF's "Segmented
> Attributes").  I have not found the time yet to finalize the proposal
> adding some examples, nonetheless it can already be found in the OSM
> Wiki (Relations/Proposed/Segmented Tags).
>
>
> Best wishes,
>  -bernd
>

Big +1 on this proposal. That's exactly what I've been thinking about
lately. It's stupid to chop up nice long ways just because the speed limit
changes or the way happens to cross a bridge.

Karl
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