[OSM-talk] Frustration of an experienced mapper

Barry Crabtree barry.crabtree at gmail.com
Thu Mar 1 22:07:49 GMT 2007


On 3/1/07, Martijn van Oosterhout <kleptog at gmail.com> wrote:
> On 2/28/07, Christoph Eckert <ce at christeck.de> wrote:
> > Segment IDs
> >
> > So here we go by a (simplyfied and theoretical) first example. Given the
> > fact you have four nodes A, B, C and D. The nodes are connected by
> > segments of the same direction, but not in the right order, due to
> > editing after their first creation. The segments therefore have the IDs
> > 10, 30, 20 instead of 10, 20, 30. Now I make them a way. Guess what
> > weird things will happen when the street gets rendered or converted to
> > a Garmin map.
> JOSM has a command to reorder segments. As far as I can tell it does
> the right thing.

But why should the user have to 'do the right thing' by remembering to have
to reorder the segments. If a way is a collection of ordered segments then
surely that should be something JOSM (or whatever editor) should do when it
makes the way.

> > Polylines would allow for curves defined by three nodes, saving a lot of
> > unnecessary nodes, segments and mouseclicks to form a bow. It would
> > therefore lead to a much reduced data size and allow for much better
> > render results.
> There's was some work on bezier curves. It would be nice to be able to
> mark a curve "bezier=yes" or "cubicspline=yes" and make nice smooth
> roads with very few points.

I think that users have been doing that pretty well manually when they
create the nodes from the original gps traces.  Thats why I think the
lines2curves.pl script works pretty well. Guess you could update the editor
to let you do this by manually curve fitting, but I suspect this would take
longer in the end than just putting in a few more points and have it done


> Currently OSM lives from collecting new data, but editing data will
> > become more and more important. Thus I can imagine that we need some
> > improvements on the data model, which not only address the issues
> > mentioned above but even others. Someone savvy here who can contribute
> > some technical/mathematical knowledge about those issues?

Whats happening with the  thoughts brought up a while back about removing
segments entirely?

Well, the SVG format supports bezier curves and cubic splines, so one
> would think that it would be easy to configure it for ways...
> Possibly though renderers don't support it yet...

getting there....

Have a nice day,
> --
> Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/
> _______________________________________________
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> talk at openstreetmap.org
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Cheers Baz.

Live as if you were to die tomorrow. Learn as if you were to live
forever.  - Gandhi.
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