[Qgis-developer] Re: [Qgis-user] Announcing RoadGraph plugin

[Maurício de Paulo]

What I meant for topology is that one can set a snapping tolerance different
than the snapping tolerance.
For instance, someone would like to snap with 100m so it's easier for the
person to identify the features. But this same person has a pretty well
constrained dataset and it should use topology tolerance of 1m. So sometimes
it's a good thing that the topology tolerance and the snapping tolerance are
not equal.

For topology tolerance I mean the maximum distance between two points for
the system to understand them as one point only.
Usually it depends on the data's mapping scale.
IMHO it would be desirable for roadgraph to use a tolerance for the
endpoints also. This way users could work even with a dataset not so well
built. What do you guys think?
Best regards,
Mauricio de Paulo


2011/1/28 Sergey Yakushev <yakushevs at list.ru>

>
>
>
> Fri, 28 Jan 2011 12:40:54 -0200 письмо от MaurМcio de Paulo <
> mauricio.dev at gmail.com>:
>
> > I was asked once: does roadgraph plugins read the layer's snap
> information from project settings?
> No, roadgraph plugin don't read snap information. But it is a good idea.
> For snap point road graph plugin calculate distance to each line's segment
>  and select minimum.
>
> >  Or does it set a topology tolerance or itself?
> Sorry, I don't understand you. Please explain it.
>
> > All the best,
> > Mauricio de Paulo
>
> > 2011/1/28 Sergey Yakushev <yakushevs at list.ru>
> > Hi Tim.
> >
> > 1. You need to configure the plugin ("Plugins => road graph => settings")
> >
> > 2. "Plugins => road graph => show roads direction" for highlight roads
> direction. I use this for testing settings.
> >
> > 3. Road graph plugin have problem with tie point to graph. Try for very
> short path and big scale (e.g. 1:1).
> >
> > Thu, 27 Jan 2011 23:37:46 +0200 письмо от Tim Sutton <
> lists at linfiniti.com>:
> >
>
> > > Hi Sergey
> > >
> > > I tried to test the plugin tonight (Ubuntu 10.10) - I see the
> > > roadgraph dock, click on the start and end points on my road network,
> > > but nothing happens when I click the compute button. Am I missing
> > > something?
> > >
> >
> > --
> > С уважением Якушев Сергей yakushevs at list.ru
> >
> > _______________________________________________
> >
> > Qgis-developer mailing list
> > Qgis-developer at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/qgis-developer
> >
>
>
> > --
> > Mauricio de Paulo
> > Engenheiro Cartografo
> > MapeandoOBrasil
>
> >
>
> --
> С уважением Якушев Сергей yakushevs at list.ru
>
>


-- 
Mauricio de Paulo
Engenheiro Cartografo
MapeandoOBrasil <http://mapeandoobrasil.blogspot.com>
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