What I meant for topology is that one can set a snapping tolerance different than the snapping tolerance.<br>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.<br>
<br>For topology tolerance I mean the maximum distance between two points for the system to understand them as one point only.<br>Usually it depends on the data's mapping scale.<br>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?<br>
Best regards,<br>Mauricio de Paulo<br><br><br><div class="gmail_quote">2011/1/28 Sergey Yakushev <span dir="ltr"><<a href="mailto:yakushevs@list.ru">yakushevs@list.ru</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<br>
<br>
<br>
Fri, 28 Jan 2011 12:40:54 -0200 письмо от MaurМcio de Paulo <<a href="mailto:mauricio.dev@gmail.com">mauricio.dev@gmail.com</a>>:<br>
<div class="im"><br>
> I was asked once: does roadgraph plugins read the layer's snap information from project settings?<br>
</div>No, roadgraph plugin don't read snap information. But it is a good idea.<br>
For snap point road graph plugin calculate distance to each line's segment and select minimum.<br>
<div class="im"><br>
> Or does it set a topology tolerance or itself?<br>
</div>Sorry, I don't understand you. Please explain it.<br>
<div class="im"><br>
> All the best,<br>
> Mauricio de Paulo<br>
<br>
> 2011/1/28 Sergey Yakushev <<a href="mailto:yakushevs@list.ru">yakushevs@list.ru</a>><br>
</div><div class="im">> Hi Tim.<br>
><br>
> 1. You need to configure the plugin ("Plugins => road graph => settings")<br>
><br>
> 2. "Plugins => road graph => show roads direction" for highlight roads direction. I use this for testing settings.<br>
><br>
> 3. Road graph plugin have problem with tie point to graph. Try for very short path and big scale (e.g. 1:1).<br>
><br>
> Thu, 27 Jan 2011 23:37:46 +0200 письмо от Tim Sutton <<a href="mailto:lists@linfiniti.com">lists@linfiniti.com</a>>:<br>
><br>
<br>
> > Hi Sergey<br>
> ><br>
> > I tried to test the plugin tonight (Ubuntu 10.10) - I see the<br>
> > roadgraph dock, click on the start and end points on my road network,<br>
> > but nothing happens when I click the compute button. Am I missing<br>
> > something?<br>
> ><br>
><br>
> --<br>
> С уважением Якушев Сергей <a href="mailto:yakushevs@list.ru">yakushevs@list.ru</a><br>
><br>
> _______________________________________________<br>
><br>
</div><div class="im">> Qgis-developer mailing list<br>
> <a href="mailto:Qgis-developer@lists.osgeo.org">Qgis-developer@lists.osgeo.org</a><br>
> <a href="http://lists.osgeo.org/mailman/listinfo/qgis-developer" target="_blank">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a><br>
><br>
<br>
<br>
</div><div class="im">> --<br>
> Mauricio de Paulo<br>
> Engenheiro Cartografo<br>
> MapeandoOBrasil<br>
<br>
><br>
<br>
</div><div><div></div><div class="h5">--<br>
С уважением Якушев Сергей <a href="mailto:yakushevs@list.ru">yakushevs@list.ru</a><br>
<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>Mauricio de Paulo<br>Engenheiro Cartografo<br><a href="http://mapeandoobrasil.blogspot.com" target="_blank">MapeandoOBrasil</a><br><br>