[OSM-talk] How do I tag this road in OSM

[Etienne]

On 8/2/06, Lars Aronsson <lars at aronsson.se> wrote:
>
> SteveC wrote:
>
> > When OSM started a few people said 'rah rah WSF-T rah rah'.
>
> Say again, what's WSF-T?
>
> > figured that I'd just do anything practical to get things going.
> > This meant nodes and segments.
>
> Yes, a very good decision at the time.  But we're beginning to see
> different scalability problems now, exactly because you
> successfully did get things going.  Maybe it's time now or
> sometime soon to light the second stage of this rocket.
>
> I suspect, even though I haven't studied this in detail, that
> polylines (ways without line segments) is the secret why the
> combination of "shapefiles" and MapServer in many applications can
> be so fast.  Polylines with bounding boxes is a very efficient
> grouping of a large number of nodes, that can scale very nicely.
> On a nationwide map, you only have to study a handful of bounding
> boxes rather than millions of individual line segments.
>
> On top of polylines, there still needs to be larger objects.
> Each polyline by definition only runs between junctions (or street
> corners).  "King Street" or "national road 47" needs to be a group
> of many polylines.


Groups will be needed.  The best solution is to make them hierarchical so
that groups can be grouped into bigger groups and so on.  This is an elegant
and flexible design but can be a bit tricky to query and process.

Etienne

--
>   Lars Aronsson (lars at aronsson.se)
>   Aronsson Datateknik - http://aronsson.se
>
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