[Qgis-user] network building tool

[Vincent Picavet]

Hi, 

[...]
> > > Then, a procedure would read the connections from the table and draw
> > > automatically these connecting lines between the nodes.
> > 
> > If you want straight lines between nodes, it is easy. Otherwise you would
> > have > to state rules for making the lines between the nodes, and it can
> > be  simple or very complicated to automate according to the rules.
> 
> See my workflow in:
> http://thread.gmane.org/gmane.comp.gis.qgis.user/24511/focus=24527

If it is a matter of changing the last vertex of an already existing geometry, 
it is doable and quite easy, even if a bit more complicated than a simple 
makeline.

> > Here is a PostGIS example of creating the edge geometry given to/from
> > nodes : https://gist.github.com/vpicavet/7572293
> 
> Do you think that this could be done as well with non-server based storage
> (shapefile, sqlite/spatialite)?
With spatialite you may be able to do the same thing, as sqlite has triggers 
too, but it is not as easy. You cannot create custom functions, so if your 
edge geometry creation is very complex it will probably be very tricky.

> > This behaviour is transparent for a visualization client, QGIS for
> > exemple.
> 
> Great. give me some time to test on it.
ok

Vincent

> 
> Thanks for your follow-up.
> 
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